Inflator

ABSTRACT

The present invention is an inflator with an improved reliability wherein a charge holder  37  for giving directivity to an detonation wave generated due to combustion of a priming  36  is provided to an igniter  26,  thereby promoting rupture of a rupturable plate  19.  A cross-shaped notch is applied to a surface of the rupturable plate  19,  and when the rupturable plate  19  receives a rupture pressure from the igniter  26,  four portions of the rupturable plate lap so that the outflow of the pressurized medium can be secured and fragments cannot be made. An inflator housing  12  and a diffuser  20  are connected by screwing a male screw portion on an outer surface of the end portion in the inflator housing  12  into a female screw portion on an inner surface of the end portion in the diffuser portion  20.  An existing gas cylinder can be used in this method. A diffuser portion  320  is connected in the opening portion side of a housing  312,  and a gas discharging port  340  is connected to the diffuser portion  320.  The outflow direction of the pressurized medium and the axial directions of the inflator housing  312  and the gas discharging port  340  are coincident with each other at actuation. The diffuser portion  520  is connected in the opening portion side of the inflator housing  512,  and the gas discharging port  540  is connected to the diffuser portion  520,  and two filter means  400   a  and  400   b  are arranged. After actuation, foreign objects included in the pressurized medium can be removed by the filter means  400   a  and  400   b.

TECHNICAL FIELD WHERE THE INVENTION BELONGS

[0001] The present invention relates to an inflator mounted in variouskinds of vehicles for protecting a passenger when the vehicle receivedthe impact mainly from the sides, and an air bag apparatus using thesame. The present invention also relates to filter means therefor, andan inflator and an air bag apparatus using the same.

BACKGROUND ART

[0002] As an inflator for an inflating type safety system of anautomobile, in order to optimally protect a passenger in accordance witha position of a seat in a vehicle such as a driver side, a passengerside and the like, there are known various inflators such as an air baginflator for a driver side, an air bag inflator for a passenger side, anair bag inflator for a side collision, an inflator for a curtain airbag, an inflator for a knee-bolster, an inflator for an inflatable seatbelt, an inflator for a tubular system and an inflator for pretensioner.Among these inflators, the inflator for a curtain air bag inflates anddevelops an air bag instantaneously to form a curtain having a thicknessof some centimeters over windows of a vehicle when the vehicle receivedthe impact from the sides.

[0003] Such an inflator for a curtain air bag is structured such thatdischarge of pressurized medium starts by rupture of a rupturable plateand a curtain air bag is inflated and developed finally. Since so-calledenhancer agent (a transfer charge) is not used, it is important toincrease the rupturability of the rupturable plate in order to improvereliability in the operation of the inflator.

[0004] Not only the above inflator for a curtain air bag but alsovarious inflators are required to be reduced in weight according to therequirement for weight reduction of a vehicle itself and simultaneouslythey are also required to be enhanced safety in actuation thereof. Forexample, when the inflator for a curtain air bag is actuated to inflateand develop the curtain air bag, a passenger views the curtain air bagand comes in contact therewith. Therefore, if foreign objects areinserted in the air bag, the passenger can be uneasy or alarmed or theair bag can be damaged. Accordingly, in a case that the inflator isprovided as a product, it becomes important to eliminate such a problem.

[0005] In order to reduce size and weight, a manufacturing process of aninflator needs to be simplified because of a demand for reduction in thenumber of parts or manufacturing cost.

[0006] As related conventional techniques, a device for inflating aflexible container using helium and hydrogen is disclosed in U.S. Pat.No. 5,527,066. A gas flow device for an air bag using a pressurizedinert gas is disclosed in U.S. Pat. No. 5,782,486. An air bag apparatusfor inflating an air bag with nitrogen or helium is disclosed in U.S.Pat. No. 3,680,886. A side-collision inflator housing for an air bagusing a pressurized gas and a gas generating agent is disclosed in U.S.Pat. No. 5,803,493. A pressurized gas inflator using argon or nitrogenas a pressurized gas is disclosed in JP-U No. 3031246.

DISCLOSURE OF INVENTION

[0007] An object of the present invention is to provide an inflator inwhich reduction in size and weight is realized and reliability inoperation is improved, and to provide an air bag apparatus using thesame.

[0008] The inflator of the present invention can be applied to any oneof an inflator for a curtain air bag, a side-collision inflator. Thefollowing is described in the case of the present invention applied tothe inflator for a curtain air bag.

[0009] The present invention (I) relates to a structure and method inwhich an outflow path of a pressurized medium is closed with arupturable plate and the rupturable plate is ruptured, and it includesaspects (I-1), (I-2) and (I-3). The present invention (II) relates to astructure and method for controlling outflow of the pressurized medium.The present invention (III) relates to filter means and an inflatorusing the same. Also, the present invention relates to an air bagapparatus mounted with the inflator. The respective aspects will beexplained below.

[0010] (I-1)

[0011] As a means for solving the above problem, the present inventionprovides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is connected to the opening portion ofthe inflator housing and is provided with a gas discharging port fordischarging the pressurized medium flowing from the opening to theoutside at actuation, a rupturable plate closing an outflow path for thepressurized medium between the diffuser portion and the opening portionof the inflator housing, and an igniter which includes a priming forrupturing the rupturable plate by an detonation wave and is provided inthe diffuser portion, wherein one or combination of at least tworequirements selected from the following requirements (a) to (d) areprovided:

[0012] (a) the igniter has a charge holder for giving directivity todetonation waves generated due to combustion of the priming.

[0013] (b) the igniter has a cup arranged to include at least a primingtherein and the cup has a fragile portion in a portion facing therupturable plate.

[0014] (c) an explosive is attached on the surface of the rupturableplate.

[0015] (d) the rupturable plate has a fragile portion.

[0016] In the requirement (a), the charge holder is arranged to surroundat least a priming of the igniter from the outside and a side thereoffacing the rupturable plate can be open.

[0017] By providing the charge holder in this manner to give thedirectivity to the detonation wave (flame) generated due to combustionof the priming, in other words, to direct the detonation wave towardsthe rupturable plate, the rupturable plate can be ruptured moreunfailingly so that the reliability in operation can be enhanced.

[0018] In the requirement (b), the fragile portion in the cup can beformed by providing a notch or a thinner part on the portion facing therupturable plate. Also, the fragile portion in the cup may be providedon either of an outer surface or an inner surface of a portion facingthe rupturable plate.

[0019] Further in the requirement (b), the fragile portion in the cupmay be formed by providing one line notch or providing two or more linenotches crossing perpendicularly to each other or crossing obliquelythereto on a portion facing the rupturable plate, or by making theportion thinner in a circular shape or a shape similar thereto. Here,the two line notches being perpendicular to each other are across-shaped notch, and the two or more line notches crossing obliquelyare a X-like shaped notch, a Y-like shaped notch or the like.

[0020] As described above, by providing the portion of the igniter cupfacing the rupturable plate with the fragile portion, the cup isruptured at the fragile portion when the igniter is activated to igniteand burn the priming. Therefore, an detonation wave (flame) which haspassed through a ruptured portion advances straightly in a narrow widthtowards the rupturable plate so that the rupturable plate can beruptured more securely, thereby improving the reliability in operation.

[0021] In the requirement (c), such a structure can be employed that anexplosive can be attached to the rupturable plate in the side facing theigniter.

[0022] If an explosive is attached to the rupturable plate in thismanner, an detonation wave reaches the rupturable plate to heat therupturable plate so that the rupturable plate can be ruptured moresecurely by an action of the explosive ignited and burnt by the heat,and consequently, the reliability in operation can be improved.

[0023] In the requirement (d), such a structure can be employed that thefragile portion can be formed by partially notching or by making athinner portion. This fragile portion may be provided on either of thesurfaces of the rupturable plate.

[0024] Further in the requirement (d), the fragile portion can be formedby providing two or more line notches being partially perpendicular oroblique to each other, or making a thinner portion in a circular shapeor a shape similar thereto. Here, the two line notches crossingperpendicular to each other are a cross-shaped notch, and the two ormore line notches crossing obliquely are a X-like shaped notch, a Y-likeshaped notch or the like.

[0025] By providing the rupturable plate with the fragile portion inthis manner, the rupturable plate is ruptured at the fragile portionwhen the igniter is actuated to ignite and burn the priming. Therefore,the rupturable plate can be ruptured more securely, thereby improvingthe reliability in operation.

[0026] In the inflator of the present invention, such a structureincluding one requirement selected from the above requirements (a) to(d), a combination of two requirements, a combination of threerequirements or a combination of four requirements can be employed, butit is preferable that a structure includes the requirements (a) and (b).

[0027] In the inflator of the present invention, such a structure can beemployed that the igniter and the rupturable plate are disposed to faceeach other at a predetermined interval, for example, an interval ofabout 5 mm or less. Here the predetermined interval means an intervalwhich is long enough not to disturb outflow of the pressurized mediumsince outflow of the pressurized medium may be disturbed in case of tooclose arrangement of the rupturable plate and the igniter.

[0028] In the inflator of the present invention, the rupturable platecan be in a bowl-like shape projecting towards the igniter.

[0029] In each of the above inventions, the rupturable plate may bemounted to the opening portion of the inflator housing or the diffuserportion.

[0030] (I-2)

[0031] The present invention has solved such a problem as improvement insafety at a time of actuation by providing one of three requirements (a)to (c), a combination of the requirements (a) and (b), a combination ofthe requirements (a) and (c), a combination of the requirements (b) and(c), or a combination of all the three requirements.

[0032] That is, the present invention provides as the solving means ofthe above problem, provides an inflator comprising an inflator housingin which a pressurized medium is charged and one end is provided with anopening, a diffuser portion which is connected to the opening portion ofthe inflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at actuation, the rupturable plate closing outflow path forthe pressurized medium between the opening of the inflator housing andthe diffuser portion, and an igniter which includes a priming forrupturing the rupturable plate by an detonation wave and is provided inthe diffuser portion, wherein one or combination of at least tworequirements selected from the following requirements (a) to (d) areprovided:

[0033] (a) the rupturable plate has a notch.

[0034] (b) a filter is arranged at the gas discharging hole.

[0035] (c) a chemical agent containing perchlorate as a main componentin an amount of 280 mg or less is used as a priming for rupturing therupturable plate.

[0036] In the requirement (a), the notch provided on the rupturableplate acts such that the rupturable plate is ruptured from the portionprovided with the notch when the rupturable plate receives a pressuredue to an detonation wave (flame) and acts such that any fragment arenot made.

[0037] In order to achieve such actions, it is preferable that therupturable plate has two or more line notches crossing perpendicularlyto each other or obliquely, and these notches on the rupturable plateare formed in a cross shape, a X-like shape, a Y-like shape or the like.For example, in case of the rupturable plate having the cross-shapednotch or the X-like shaped notch, the rupturable plate imparted with arupturing pressure laps at four portions in the crossing portion of thenotches to open, so that the pressurized medium starts being dischargedand fragments are not made.

[0038] In the requirement (b), the filter can be arranged inside oroutside the gas discharging hole, and the gas discharging hole can alsobe formed with a filter.

[0039] In the requirement (b), such a structure can be employed that agas discharging port connected at the gas discharging hole is furtherprovided, and the pressurized medium flowing out from the gasdischarging hole flows out from an opening portion of the gasdischarging port via the gas discharging port, and the filter isarranged in the gas discharging port.

[0040] Further in the requirement (b), such a structure may be employedthat the filter is disposed in the opening portion of the gasdischarging port.

[0041] With such an arrangement of a filter, if any fragments are madefrom the rupturable plate or combustion residue (oxide) of the primingare generated, the fragments and part of the combustion residue areremoved from the flowing pressurized medium, so that the fragments andresidue can be prevented from flowing into the air bag. Thereby, it ispossible to prevent that passenger is uneasy or alarmed and that the airbag is damaged. Also, by disposing the filter outside the gasdischarging hole, a pressure applying to the filter can be reduced ascompared with a case of the filter disposed inside, thereby suppressingdamage to the filter.

[0042] In the requirement (c), it is preferable that the chemical agentcontaining perchlorate as a main component and used as a priming is achemical agent containing zirconium/potassium perchlorate as a maincomponent, and it is preferable that the rupturable plate is a nickelbase alloy with corrosion resistance and with a thickness of 0.8 mm orless.

[0043] By associating the strength of the rupturable plate with thepressure of the detonation wave for rupturing the rupturable plate,namely, the kind and amount of the priming, the rupturable plate cansecurely be ruptured at actuation and the amount of the generatedcombustion residue of the priming (oxide of the priming components) canbe limited to the minimum.

[0044] In each of the above inventions, the rupturable plate can bemounted to the opening portion of the inflator housing or the diffuserportion.

[0045] (I-3)

[0046] An object of the present invention is to provide an inflatorcapable of facilitating the producing process, enhancing the pressureresistance and durability of the product, and reducing a size and weightthereof, and to provide an air bag apparatus using the same.

[0047] The inflator of the present invention can be used as an inflatorfor a curtain air bag or a side-collision inflator. The following isdescribed in the case of the present invention applied to the inflatorfor a curtain air bag.

[0048] As a solving means of the above problem, the present inventionprovides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is connected to the opening portion ofthe inflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at actuation, a rupturable plate closing an outflow path forthe pressurized medium between the diffuser portion and the openingportion of the inflator housing, and a rupturing means for therupturable plate provided in the diffuser portion, wherein therupturable plate is mounted at an annular member fitted to be integratedwith the opening portion of the inflator housing.

[0049] In the present invention, such a structure can be employed thatthe pressurized medium is charged from a clearance between a rim of theopening portion in the inflator housing and the annular member, and theopening portion of the inflator housing and the annular member arejoined to each other by a resistance-welding.

[0050] Generally, when the pressurized medium is charged into theinflator housing, a thin hole is provided at part of the inflatorhousing, a sealing pin is inserted into the thin hole so that a littleclearance is obtained in the thin hole, the pressurized medium ischarged through a groove provided at the sealing pin, and thereafter theinflator housing and the sealing pin are welded together to be sealed.However, according to the method of the invention, the charging processof the pressurized medium can be simplified.

[0051] Also, as the solving means of the above object, the presentinvention provides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is connected to the opening portion ofthe inflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at actuation, a rupturable plate closing an outflow path forthe pressurized medium between the diffuser portion and the openingportion of the inflator housing, and a rupturing means for therupturable plate provided in the diffuser portion, wherein the inflatorhousing is connected to the diffuser portion by screwing.

[0052] In this invention, such a structure can be employed that theconnection of the inflator housing and the diffuser portion is achievedby screwing a screw portion on an outer surface of an end portion in theinflator housing to a screw portion on an inner surface of an endportion in the diffuser portion. The respective screw portions can beeither of a female screw portion and a male screw portion.

[0053] In this manner, by screwing the inflator housing to the diffuserportion, an existent inert gas cylinder can be directly used as aconstituent member, thereby facilitating the manufacturing process andreducing the manufacturing cost.

[0054] Since the inflator (I-1) of the present invention has meansselected from the requirements (a) to (d), the rupture of the rupturableplate is enhanced so that the reliability in operation of the inflatorat actuation thereof becomes high. In case that the inflator (I-1) isused as a side-collision inflator, the gas discharging port 40 is notrequired, and an air bag is connected to the gas discharging hole 22directly or via a suitable adapter.

[0055] The inflator (I-2) of the present invention is improved in safetyat actuation by employing at least one requirement selected from therequirements (a) to (c).

[0056] Since the inflator (I-3) of the present invention has a simplestructure so that the manufacturing steps can be simplified.

[0057] Next, object of the present invention is to provide an inflator(II) in which a size and weight can be reduced and facility inassembling to an air bag apparatus as well as in mounting to a vehicleand safety at actuation or at transportation is improved, and to providean air bag apparatus using the same.

[0058] The inflator (II) of the present invention can be used as aninflator for a curtain air bag or a side-collision inflator, but thefollowing is describe in case of the present invention applied to theinflator for a curtain air bag.

[0059] As a solving means of the above problem, the present inventionprovides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an opening, adiffuser portion which is fixed to the opening portion of the inflatorhousing and is provided with a gas discharging hole for discharging thepressurized medium flowing from the opening portion to the outside atactuation, a rupturable plate closing an outflow path for thepressurized medium between the diffuser portion and the opening portionof the inflator housing, and a rupturing means for the rupturable plateprovided in the diffuser portion, wherein the outflow direction of thepressurized medium at actuation is coincident with the axial directionof the inflator housing.

[0060] As described above, by making the outflow direction of thepressurized medium coincident with the axial direction of the inflatorhousing, the mounting direction of the inflator and the inflatingdirection of the curtain air bag are coincident with each other so thatthe mounting of the inflator in the vehicle is facilitated.

[0061] Further, as other solving means of the above problem, the presentinvention provides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an opening, adiffuser portion which is fixed to the opening portion of the inflatorhousing and is provided with a gas discharging hole for discharging thepressurized medium flowing from the opening portion to the outside atactuation, a rupturable plate closing an outflow path for thepressurized medium between the diffuser portion and the opening portionof the inflator housing, and a rupturing means for the rupturable plateprovided in the diffuser portion, wherein a gas discharging portconnected to the gas discharging hole is further provided, and thepressurized medium discharged from the gas discharging hole passes thegas discharging port to be discharged from the opening portion of thegas discharging port.

[0062] In this invention, since a location and direction of the openingportion (outflow opening of the pressurized medium) of the gasdischarging port are not limited, by mounting the gas outflow port tothe gas discharging hole of the inflator to discharge the pressurizedmedium therefrom, the mounting is facilitated as compared with a casesuch that the curtain air bag is mounted to the inflator housing, andthereby, the outflow direction of the pressurized medium can also beoptionally controlled.

[0063] The above gas discharging port may has a structure such that thegas discharging port and the inflator housing are mounted so that theaxial directions of the both are parallel to each other.

[0064] Also, as still other solving means of the above problem, thepresent invention provides an inflator comprising an inflator housing inwhich a pressurized medium is charged and one end is provided with anopening, a diffuser portion which is fixed to the opening portion of theinflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at actuation, a rupturable plate closing an outflow path forthe pressurized medium between the diffuser portion and the openingportion of the inflator housing, and a rupturing means for therupturable plate provided in the diffuser portion, wherein the gasdischarging port is disposed in the extension of the center line of theopening portion in the inflator housing, and the pressurized mediumdischarged from the gas discharging hole passes the gas discharging portto be discharged from the opening portion of the gas discharging port.

[0065] With such a structure, the pressurized medium is dischargedsmoothly, and the widthwise size (in radial direction) of the inflatorcan be reduced.

[0066] In the above invention, the pressurized medium passes the openingportion of the inflator housing, the inner space of the diffuser portionand the gas discharging port to be discharged from the opening portionof the gas discharging port without changing the outflow direction ofthe pressurized medium.

[0067] In the above invention, the rupturing means for the rupturableplate provided in the diffuser portion can be arranged to face the innerspace of the diffuser portion and to position slantingly with respect tothe central line of the rupturable plate. Here, “to position slantingly”means that the central axis of the rupturing means crosses slantinglythe central line of the rupturable plate.

[0068] Further, it is preferable that an angle (θ) formed between thecentral axis of the rupturing means for the rupturable plate provided inthe diffuser portion and the central line of the rupturable plate isacute, more preferably, 10° to less than 90°, further preferably, 40° to50°. When the angle θ is acute, the widthwise size of the inflator canbe small, and the rupturable plate can securely be ruptured, so thatoutflow of the pressurized medium cannot be blocked.

[0069] By adjusting the arrangement of the rupturing means and therupturable plate in this manner, the rupturable plate can securely beruptured at a time of actuation of the inflator without enlarging thesize, in the widthwise direction, of the inflator.

[0070] Furthermore, in the above invention, the rupturing means for therupturable plate provided in the diffuser portion can be arranged toface the inner space of the diffuser portion and to cross the centralline of the rupturable plate perpendicularly. At this time, it ispreferable that the rupturable plate closes the outflow path of thepressurized medium in the inner space of the diffuser portion and partof the rupturable plate faces the rupturing means. Furthermore,preferably, the rupturable plate is a cylindrical member having one endclosed and the other end open, the plate closes the outflow path of thepressurized medium with its closed end and the peripheral surface, andpart of the peripheral surface faces the rupturing means.

[0071] By adjusting the arrangement of the rupturing means and therupturable plate in this manner and by changing the shape of therupturable plate with reference to the arrangement, the outflow path ofthe pressurized medium can completely be closed before actuation and therupturable plate can securely be ruptured at actuation without enlargingthe widthwise size of the inflator.

[0072] Furthermore, the above gas discharging port can have such astructure that it comprises a cylindrical member having one end closedand the other end open and the pressurized medium flows out from theopening portion.

[0073] In case of using such a gas discharging port, since the outflowdirection of the pressurized medium from the gas discharging port andthe axial direction of the inflator housing are coincident with eachother, the mounding direction of the inflator and the inflatingdirection of the curtain air bag are coincident with each other, therebyfacilitating mounting of the inflator to the vehicle.

[0074] In the inflator of each of the above inventions, such a structurecan be employed that a filter for removing foreign objects in theflowing pressurized medium is provided inside or outside the gasdischarging hole, or the gas discharging hole itself is formed with thefilter.

[0075] Further, in the inflator of each of the above inventions, such astructure can be employed that a filter for removing foreign objects inthe flowing pressurized medium is provided inside the gas dischargingport.

[0076] Further, in the inflator of each of the above inventions, such astructure can be employed that a filter for removing foreign objects inthe flowing pressurized medium is provided at the opening portion of thegas discharging port.

[0077] In the inflator, the pressurized medium starts discharging due torupture of the rupturable plate at actuation, when fragments may bemade, and the fragments flow out together with the pressurized medium toreach the inside of the curtain air bag to damage the air bag.Therefore, by arranging the filter in the above manner, inflow of thefragments into the air bag can be prevented.

[0078] In the inflator of the above invention, in case of the structuresuch that the gas discharging port is mounted, such a structure can beemployed that an adapter for discharging the pressurized medium in thecircumferential direction is mounted to the opening portion of the gasdischarging port to be attached and removed optionally.

[0079] In case that such a structure is employed, even if a fire breaksout at a time of storage before mounting to a vehicle or transportationand the like, and then a contingent happens such that the rupturingmeans is activated and ruptures the rupturing plate, the pressurizedmedium is discharged in the circumferential direction due to action ofthe adapter. Thereby, the inflator itself is prevented from beingejected like a rocket due to eject of the pressurized medium in such amanner as the pressurized medium is ejected in one direction.

[0080] Also, as a solving means of the above problem, the presentinvention provides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is fixed to the opening portion of theinflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening to theoutside at actuation, a rupturable plate closing an outflow path for thepressurized medium between the diffuser portion and the opening portionof the inflator housing, and a rupturing means for the rupturable plateprovided in the diffuser portion, wherein an outflow amount of thepressurized medium at actuation is controlled by a gas discharging holeor a filter provided at the gas discharging hole.

[0081] Here, a case such that the filter is provided at the gasdischarging hole includes not only a case that the filter is providedinside or outside the gas discharging hole but also a case that the gasdischarging hole itself is formed with the filter.

[0082] In the above invention, such a structure can be employed that thefilter is a annular shape, it covers the gas discharging hole of thediffuser portion from the inside and it is arranged to capture foreignobjects contained in the pressurized medium, and further an annularspace having a sectional area in the radial direction larger than anopening area of the gas discharging hole is formed between the annularfilter and the gas discharging hole to control the outflow amount of thepressurized medium at actuation of the inflator by the gas discharginghole.

[0083] Since the annular filter is for preventing foreign objects(fragments of the rupturable plate or the like) from flowing out fromthe gas discharging hole, a sectional area of the annular filter in theradial direction is set to be larger than the opening area of the gasdischarging hole. For this reason, when the pressurized medium flows outthrough the filter, the pressurized medium is concentrated on only aportion of the filter facing the gas discharging hole, namely, oneportion of the filter to flow out, so that an effective filtration cannot be achieved. As a result, the foreign objects are also concentratedon only one portion of the filter to be so clogged in the filter, sothat the outflow amount of the pressurized medium is lowered. Therefore,by providing the annular space having a sectional area larger than theopening area of he gas discharging hole, such an event can be avoided.Then, by controlling the outflow amount of the pressurized medium aswell as providing the annular space, prevention of lowering the outflowamount due to the clogging of the filter can further be effectivelyenhanced.

[0084] In view of the effect of removing foreign objects, the annularfilter is required to have a radial sectional area larger than theradial sectional area of the annular space, and preferably, the annularfilter is made of one layered porous member such as a punched metal, aplain-stitched wire mesh or the similar member or at least two layeredof the porous members.

[0085] Further, as other solving means of the above problem, the presentinvention provides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is fixed to the opening portion of theinflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at actuation, a rupturable plate closing an outflow path forthe pressurized medium between the diffuser portion and the opening ofthe inflator housing, and a rupturing means for the rupturable plateprovided in the diffuser portion, wherein a gas discharging portconnected at the gas discharging hole is provided, the pressurizedmedium discharged from the gas discharging hole passes the gasdischarging port to be discharged from the opening of the gasdischarging port, and the outflow amount of the pressurized medium atactuation is controlled by opening portion of the gas discharging portor a filter provided in the gas discharging port.

[0086] By controlling the flow amount (an outflow amount per unit time)of the pressurized medium at actuation with the gas discharging hole orthe opening portion of the gas discharging port in this manner, theoutflow amount of the pressurized medium can be prevented from beingaffected by rupture of the rupturable plate. Such a control of theoutflow amount of the pressurized medium can be performed by, forexample, the pressure loss (opening area) of the gas discharging hole orthe pressure loss of the filter.

[0087] Furthermore, as a solving means of the above problem, the presentinvention provides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is fixed to the opening portion of theinflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening to theoutside at actuation, a rupturable plate closing an outflow path for thepressurized medium between the diffuser portion and the opening of theinflator housing, and a rupturing means for the rupturable plateprovided in the diffuser portion, wherein the outflow amount of thepressurized medium at actuation is controlled by the outflow path of thepressurized medium. Also in the present invention, the gas dischargingport having the opening portion connected to the gas discharging hole ofthe diffuser portion is mounted and the pressurized medium dischargedfrom the gas discharging hole passes the gas discharging port to bedischarged from the opening portion of the gas discharging port.

[0088] By controlling the outflow amount (an outflow amount per unittime) of the pressurized medium at actuation with the outflow path ofthe pressurized medium, the outflow amount of the pressurized medium isprevented from being affected by the rupture of the rupturable plate.Such a control of the outflow amount of the pressurized medium can beperformed by, for example, the pressure loss (opening area) of theoutflow path of the pressurized medium.

[0089] In each of the above inventions, such a structure can be employedthat the gas discharging port has two or more opening portions only onthe side surface, at least two opening portions of the two or moreopening portions are positioned symmetrically in the widthwise directionor positioned similarly thereto, and a screen with a plurality ofoutflow holes is arranged at the position where the opening portion isprovided inside the gas discharging port. Here, when the number ofopening portions of the gas discharging port is two, the openingportions are positioned symmetrically in the widthwise direction.However, when the number of opening portions is three or four or more,it is preferable that the opening portions are arranged in thecircumferential direction at equal intervals.

[0090] The screen can comprise a cylinder made of one layered porousmember such as a punched metal, a plain-stitched wire mesh or thesimilar member or at least two layered of the porous members. It ispreferable that the screen is arranged such that its axial direction iscoincident with the axial direction of the gas discharging port.

[0091] As described above, by adjusting the position of the openingportion in the gas discharging port, the following effects can beobtained.

[0092] (First effect)

[0093] When a fire or the like breaks out during storage/transportationof an inflator and then an accidental event such as a malfunction of theinflator occurs, in case of a gas discharging port having, in the sidesurface, only one opening portion or closely positioned openingportions, the inflator is ejected like a rocket due to the pressurizedmedium ejected from the opening portion, which is much dangerous. Asdescribed above, however, by positioning at least two opening portionssymmetrically in the widthwise direction (in a radial direction when thegas discharging port is cylindrical) or similarly thereto, such anabnormal event is prevented.

[0094] (Second effect)

[0095] Since the opening portion is provided on the side surface of thegas discharging port, it is sufficient for the screen to function as ascreen at least in a part facing an opening portion. Therefore, aspecial member in which the positions of the opening portion and anoutflow hole of the screen is aligned with each other is not required,and a commercial punched metal, a plain-stitched wire mesh or the likecan be used directly, so that materials are inexpensive.

[0096] (Third effect)

[0097] Since the opening portion provided in the gas discharging portmay be large, it is unnecessary to enhance a size accuracy inprocessing, by which the process is facilitated.

[0098] In each of the inventions, when the inflator is connected to theair bag, such a structure can be employed that the gas discharging porthas convex portions continuously in a circumferential direction or atintervals provided on an outer surface from the at least two openings onthe side surface to a portion where an air bag is connected. At thistime, it is preferable that the convex portion is provided close to theopening.

[0099] By providing the above convex portion on the gas dischargingport, such an effect can be obtained that a smooth inflation performanceof the air bag can be secured when the air bag apparatus is actuated.When the inflator and the air bag are connected to each other, the bothare fixed and integrated with each other by a fastening means after theair bag covers the gas discharging port to surround at least openingportion. In this case, if the gas discharging port has a flat shape withan uniform diameter, the air bag contacts tightly the opening portionprovided with the side surface of the gas discharging port, so that aclearance through which the pressurized medium passes cannot be obtainedbetween the inner surface of the air bag and the opening portion.Consequently, at a time of actuation of the inflator, specifically, atthe initial stage of the actuation, smooth flow of the pressurizedmedium ejected from the opening portion in the side surface is blocked,and the inflation performance of the air bag may be disturbed. However,by providing the convex portion in the above manner, a clearance whichserves as a flow path of the pressurized medium can be secured betweenthe inner surface of the air bag and the opening portion in the sidesurface, so that such a problem as described above cannot occur.

[0100] Also, as a solving means of the above problem, the presentinvention provides an inflator in which, in connecting an air bag to aninflator having a gas discharging port having the above convex portion,when the gas discharging port is inserted into a cylindrical mouthpiecemounted to the opening portion of the air bag and the mouthpiece and thegas discharging port are connected to each other, a clearance existsbetween an inner surface of the mouthpiece and an outer surface of aninserted portion of the gas discharging port reaching the convexportion, and a sectional area of the clearance defined by a differencebetween a widthwise sectional area in the mouthpiece and a widthwisesectional area in the inserted portion of the gas discharging portreaching the projecting portion thereof is larger than the total openingarea of a outflow hole of a screen arranged at the gas discharging port,wherein the sectional area of the clearance is larger than the totalopening area of the gas discharging hole arranged at the diffuserportion.

[0101] By making the sectional area of the clearance larger than thetotal opening area of the outflow hole of the screen arranged at the gasdischarging port or the total opening area of the gas discharging holearranged at the diffuser portion, the outflow amount of the pressurizedmedium can be controlled at the screen or the gas discharging hole.

[0102] In each of the above inventions, it is preferable that a malescrew is provided on the convex portion and a female screw is providedon part of or an entire portion of the mouthpiece, more preferably, partof the mouthpiece (only part to be screwed with the male screw on theconvex portion). In order to achieve the above effect and control theoutflow amount of the pressurized medium, preferably, a width of theclearance defined between the inner surface of the mouthpiece and theouter surface of the inserted portion of the gas discharging portreaching the convex portion is 1 to 5 mm.

[0103] In each of the above inventions, the rupturable plate can bemounted to the opening portion of the inflator housing or the diffuserportion.

[0104] Since the outflow direction of the pressurized medium at a timeof actuation and the axial direction of the inflator housing arecoincident with each other, the inflator (II) of the present inventioncan inflates and develops the curtain air bag in the same direction asthe axial direction of the inflator housing. Thereby, since the inflatormay be mounted such that the direction in which the curtain air bag isdesired to be inflated and developed and the axial direction of theinflator housing are coincident with each other, a mounting process isfacilitated. Furthermore, the inflator of the present invention can beimproved in safety at actuation, transportation or the like.

[0105] An object of the present invention is to provide a filter means(III) to be mounted on an inflater such as can reduce a size and weightand is improved in mounting easiness and safety at actuation,transportation or the like, and to provide an inflator using the sameand an air bag apparatus using the same.

[0106] A filter member for an inflator of the present invention can beapplied to various inflators but it is specifically suitable for aninflator for an air bag, for example, an inflator for a curtain air bagand an inflator for side-collision. The following is described in a caseof the present invention applied to the inflator for a curtain air bag.

[0107] As a solving means of the above problem, the present inventionprovides a filter means for an inflator for removing foreign objects,comprising a disk-shaped supporting body having a predetermined numberof through holes and a filter member covering one surface or bothsurfaces of the disk-shaped supporting body.

[0108] It is preferable that the filter member of the present inventionis a punched metal or a lath metal, and preferably in a case of aregular square mesh of sieve, one side of the mesh of sieve of thefilter member is 0.4 to 2.0 mm, more preferably, 0.6 to 1.0 mm, andfurther preferably, 0.6 to 0.9 mm.

[0109] In the present invention, when both surfaces of the disk-shapedsupporting body are covered with filter members, the meshes of sieve onthe both surfaces of the filter members can be equal to each other ordifferent from each other.

[0110] It is preferable that a screw portion for mounting the filtermeans to be attached and removed optionally is provided on an outerperipheral surface of the disk-shaped supporting body of the filtermeans of the above invention.

[0111] In the inflator for a curtain air bag, the pressurized mediumstarts being discharged due to rupture of the rupturable plate atactuation, but there may be made fragments at rupture, and the fragmentsflow together with the pressurized medium to reach the inside of thecurtain air bag, thereby damaging the air bag. Therefore, by arrangingsuch a filter means as the above, the fragments can be prevented fromflowing into the air bag.

[0112] The above-described filter means for an inflator with a simplestructure can remove foreign objects generated at actuation of theinflator, for example, solid materials such as fragments of therupturable plate, and additionally, the filter means is made to beattached and removed optionally when mounted in the inflator, thereby,an assembling process is facilitated. Furthermore, since differentfilter means which can remove more than two different foreign objects(namely, filter means with different meshes of sieve) can be combined, aforeign objects removing performance can easily be adjusted according tothe capability, the structure or the like of the inflator.

[0113] As other solving means of the above problem, the presentinvention provides an inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is connected to the opening portion ofthe inflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening to theoutside at actuation, a rupturable plate closing an outflow path for thepressurized medium between the diffuser portion and the opening portionof the inflator housing, and a rupturing means for the rupturable plateprovided in the diffuser portion, and

[0114] wherein a gas discharging port which is connected to the gasdischarging hole and has one end closed and other end with an openingportion, and one or at least two described above filter means for aninflator for removing foreign objects in the discharged pressurizedmedium is provided inside the gas discharging port to be attached andremoved optionally and movable in the axial direction, and

[0115] wherein the pressurized medium discharged from the gasdischarging hole passes the gas discharging port to be discharged fromthe opening portion of the gas discharging port.

[0116] In the above invention, at least two filter means can be arrangedsuch that they come in contact with each other or they are spaced fromeach other.

[0117] In the above invention, each of at least two filter means may beformed to have the same meshes of sieve or different meshes of sieve ofthe respective filter members. In case of the mesh of sieve are madedifferent, it is preferable that the meshes of sieve become graduallysmaller from the gas discharging hole of the diffuser portion towardsthe opening portion of the gas discharging port.

[0118] According to each of the inventions, even if many foreign objectswith different sizes are contained in the pressurized medium, theforeign objects can be collected efficiently and unfailingly, and asmooth discharging of the pressurized medium cannot be disturbed.Further, the foreign object removing performance of the filter means canbe controlled to be maintained at a proper level, according to thecapability, structure or the like of the inflator.

[0119] Furthermore, in the above invention, by providing a screw portionon an inner circumferential surface of the gas discharging port andscrewing the disk-shaped supporting body of the filter means for aninflator, it is possible to be mounted to be attached and removedoptionally and movable in the axial direction.

[0120] With such a structure, it is made easy to mount the filter meansfor an inflator into the gad discharging port, and if at least twofilter means are used, the arrangement of these filter means can beadjusted easily.

[0121] Furthermore, in the above invention, the gas discharging port canbe mounted such that the axial direction of the gas discharging port andthe axial direction of the inflator housing become parallel to eachother, and an adapter for discharging the pressurized medium in thecircumferential direction can be mounted to be attached and removedoptionally at the opening portion of the gas discharging port.

[0122] In this manner, by making the outflow direction of thepressurized medium and the axial direction of the inflator housingcoincident with to each other, the mounting direction of the inflatorand the inflating direction of the curtain air bag are coincident witheach other, thereby facilitating mounting work to the vehicle.

[0123] With a structure in which an adapter is mounted, even when a firebreaks out during storage, transportation of the inflator beforemounting to the vehicle or the like and then accidentally the rupturingmeans actuates to rupture the rupturable plate, the pressurized mediumis discharged in the circumferential direction due to action of theadapter. Thereby, the inflator itself is prevented from being ejectedlike a rocket due to ejecting of the pressurized medium when thepressurized medium ejected in one direction.

[0124] An inflator assembled with the filter means of the presentinvention can be mounted easily and additionally the foreign objectremoving performance can be adjusted according to capability, structureor the like of the inflator.

[0125] Also, the present invention provides an air bag apparatuscomprising an activation signal-outputting means including an impactsensor and a control unit and a module case accommodating the aboveinflator (I), (II) or (III) and an air bag.

BRIEF DESCRIPTION OF THE DRAWINGS

[0126]FIG. 1 is a sectional view of an inflator (I) of the presentinvention in the longitudinal direction.

[0127]FIG. 2 is a partially enlarged view of the inflator shown in FIG.1.

[0128]FIG. 3 is a view for explaining a state of a cup surface or arupturable plate surface in FIG. 1.

[0129]FIG. 4 is a sectional view of other embodiment of the inflator (I)of the present invention in the longitudinal direction.

[0130]FIG. 5 is a view for explaining a manufacturing process of theinflator shown in FIG. 1.

[0131]FIG. 6 is a view for explaining a manufacturing process of theinflator shown in FIG. 1.

[0132]FIG. 7 is a view for explaining a manufacturing process of theinflator shown in FIG. 1.

[0133]FIG. 8 is a sectional view of an inflator (II) of the presentinvention in the longitudinal direction.

[0134]FIG. 9 is a sectional view of an adapter mounted to the inflator(II) in the diametrical direction.

[0135]FIG. 10 is a sectional view of other embodiment of the inflator(II) of the present invention in the longitudinal direction.

[0136]FIG. 11 is a partial sectional view of other embodiment of theinflator (II) of the present invention in the longitudinal direction.

[0137]FIG. 12 is a partial sectional view of other embodiment of theinflator (II) of the present invention in the longitudinal direction.

[0138]FIG. 13 is a sectional view of other embodiment of the inflator(II) of the present invention in the longitudinal direction.

[0139]FIG. 14 is a sectional view of other embodiment of the inflator(II) of the present invention in the longitudinal direction.

[0140]FIG. 15 is a schematically sectional view for explaining aconnection state between the inflator shown in FIG. 14 and an air bag.

[0141]FIG. 16 is a plan view of a filter means of the present invention.

[0142]FIG. 17 is a sectional view of the filter means shown in FIG. 16in the diametrical direction.

[0143]FIG. 18 is a plan view of a disk-shaped supporting bodyconstituting the filter means shown in FIG. 16.

[0144]FIG. 19 is a sectional view of an inflator of the presentinvention in the longitudinal direction.

[0145]FIG. 20 is a sectional view of an adapter mounted to the inflatorof the present invention in the diametrical direction.

[0146] Numerals in the figures will be explained.

[0147]10 inflator

[0148]12 inflator housing

[0149]14 opening portion

[0150]19 rupturable plate

[0151]20 diffuser portion

[0152]22 gas discharging hole

[0153]26 igniter

[0154]40 gas discharging port

[0155]42 communication hole

[0156]48 filter

[0157]310 inflator

[0158]312 inflator housing

[0159]314 opening portion

[0160]319 rupturable plate

[0161]320 diffuser portion

[0162]322 gas discharging hole

[0163]326 igniter

[0164]340 gas discharging port

[0165]342 communication hole

[0166]348 filter

[0167]510 inflator

[0168]512 inflator housing

[0169]514 opening portion

[0170]519 rupturable plate

[0171]520 diffuser portion

[0172]522 gas discharging hole

[0173]526 igniter

[0174]540 gas discharging port

[0175]542 communication hole

[0176]548 filter

[0177]400 filter means

PREFERRED EMBODIMENT OF THE INVENTION (I)

[0178] One embodiment of the present invention (I-1) will be explainedwith reference to the drawings. FIG. 1 is a sectional view of aninflator 10 of the invention in the longitudinal direction, and FIG. 4is a sectional view of an inflator 10 of other embodiment in thelongitudinal direction.

[0179] An inflator housing 12 has an opening portion 14 in one end andthe other end closed. A pressurized medium comprising an inert gas suchas argon, helium or a nitrogen gas is charged into the inner space 16 atthe maximum pressure of about 70,000 kPa. The inflator housing 12 in thewidthwise direction has a circular section, and the opening portion 14is also circular.

[0180] The inflator housing 12 may be formed by utilizing an existentgas cylinder, and it maybe produced by swaging a pipe. A pressurizedmedium is charged into an inflator 10 shown in FIG. 1 from an openingportion 14 of the inflator housing 12. In the inflator 10 shown in FIG.4, a pressurized medium is charged from a clearance between a thin holeand a sealing pin 13 inserted therein after a diffuser portion 20 isconnected to the inflator housing 12, and then the inflator housing 12is welded at the sealing pin 13 to be closed completely.

[0181] The diffuser portion 20 is connected in the opening portion 14 ofthe inflator housing 12. An outer shell of the diffuser portion 20 isformed of a diffuser housing 23 and a gas discharging hole 22 fordischarging the pressurized medium outside is provided on the peripheryof the outer shell.

[0182] The inflator housing 12 and the diffuser portion 20 may beconnected by a welding or they may be connected by screwing a male screwportion provided on the periphery of the end portion in the inflatorhousing 12 into a female screw portion provided on the inner peripheralsurface of the end portion in the diffuser portion 20.

[0183] The opening portion 14 of the inflator housing 12 is closed witha rupturable plate 19 in a bowl-like shape, and, before actuation of theinflator, the inner space 16 of the inflator housing 12 is maintained ata high pressure in a hermetic state. A gas discharging hole 22 of thediffuser portion 20 is not closed.

[0184] An igniter 26 having a priming is provided in the diffuserportion 20 as a rupturing means for the rupturable plate 19. The igniter26 is fitted into the diffuser housing 23 to be mounted to the diffuserportion 20. Numeral 30 denotes a connector, and 32 denotes a lead wirefor connecting to a power supply.

[0185] A gas discharging port 40 is connected to the diffuser portion20, and they are connected at a welded portion 44 by welding after thegas discharging hole 22 of the diffuser portion 20 and a communicationhole 42 of the gas discharging port 40 are met with each other.

[0186] The gas discharging port 40 is mounted such that the central axis(shown in a dotted chain line in FIG. 1) of the inflator housing 12 andthe central axis (shown in a dotted chain line in FIG. 1) of the gasdischarging port 40 is parallel to each other.

[0187] The gas discharging port 40 comprises a cylindrical member havingone end closed and the other end formed with an opening portion 46, anda filter 48 for removing foreign objects is provided in the vicinity ofthe opening portion 46. An example of the filter 48 can be a wire meshor a laminated body of wire mesh. A location of the filter 48 is notparticularly limited if foreign objects can be removed from thedischarging pressurized medium. For example, the filter 48 can bedisposed to cover the communication hole 42 from the flow-path 49 of thepressurized medium.

[0188] In the inflator 10 of the present embodiment, means described inthe requirements (a) to (d) are provided as means for enhancing ruptureof the rupturable plate 19.

[0189] (1) A means shown in the requirement (a)

[0190] As shown in FIG. 2, in the igniter 26, a cylindrical chargeholder 37 is provided to surround an igniting portion 35 and adisk-shaped priming 36, and a side, of the charge holder 37, facing therupturable plate 19 is open. This charge holder 37 gives directivity todetonation waves generated due to combustion of the priming.Incidentally, numeral 38 denotes a cup in the requirement (b).

[0191] (2) A means shown in the requirement (b)

[0192] The cup 38 is arranged to include the igniting portion 35 and thepriming 36 of the igniter 26, and as shown in FIG. 3, a cross-shapednotch as a fragile portion is applied on an outer surface, in the cup38, which faces the rupturable plate 19, so that the cup 38 is rupturedat the cross-shaped notch and the directivity is given to the detonationwave.

[0193] (3) A means shown in the requirement (c)

[0194] A small amount of an explosive 39 is attached to a convex surfaceof the bowl-like rupturable plate 19, and when this part is heated, theexplosive is ignited and burnt by the heat, thereby promoting rupture ofthe rupturable plate 19.

[0195] (4) A means shown in the requirement (d)

[0196] The cross-shaped notch of the fragile portion, as shown in FIG.3, is applied to a convex surface or a concave surface of the bowl-likerupturable plate 19, so that rupture of the rupturable plate 19 ispromoted by the cross-shaped notch.

[0197] Next, other embodiment shown in FIG. 4 will be described. Aninflator 10 shown in FIG. 4 has the same structure as the inflator 10shown in FIG. 1 except for a location of a rupturable plate 19 and amethod of charging a pressurized medium (the sealing pin 13 isprovided).

[0198] In the inflator 10 shown in FIG. 1, the rupturable plate 19 ismounted to the opening portion 14 of the inflator housing 12, but in theinflator 10 shown in FIG. 4, the rupturable plate 19 is mounted to a rimof an opening 21 of the diffuser portion 20. The opening portion 14 ofthe inflator housing 12 and the opening 21 of the diffuser portion 20may be arranged to abut each other. However, as shown in FIG. 3, it isdesirable that they are arranged to obtain a clearance between theopening portion 14 and the rupturable plate 19. The size of theclearance can be adjusted by properly setting the length from theopening 21 to a tip end portion 23 a of the diffuser housing 23 in thediffuser portion 20. In this case, joining by welding can be easilyperformed by abutting the tip end portion 23 a against an expandedportion 15 of the inflator housing 12.

[0199] Next, the operation of the inflator 10 of the present inventionwill be described. At the time of being mounted to a vehicle, theinflator 10 is disposed, being included in a system comprising such asan activation signal-outputting means which comprises an impact sensorand a control unit, and a module case accommodating the above-describedinflator 10 and a curtain air bag. The curtain air bag is connected atthe opening portion 46 of the gas discharging port 40.

[0200] First, when the vehicle receives an impact, the igniter 26 isactivated upon receiving the signal from the impact sensor of thesystem, and the priming is ignited and burnt so that the rupturableplate 19 is ruptured. By providing the means described in therequirements (a) to (d), rupture of the rupturable plate 19 is promotedat the time of rupturing.

[0201] Since the opening portion 14 is opened due to the rupture of therupturable plate 19, the pressurized medium in the inner space 16 flowsout from the gas discharging hole 22 into the gas discharging port 40via the communication hole 42, and further, it is discharged from theopening portion 46 via the filter 48 to inflate the curtain air bag.Incidentally, even if fragments are made at the rupture of therupturable plate 19, they are removed by the filter 48 so that they areprevented from being discharged into the curtain air bag.

[0202] Next, an embodiment of the present invention (I-2) will bedescribed with reference to the drawings. FIG. 1 is a sectional view ofthe inflator 10 of the present invention in the longitudinal direction,and FIG. 4 is a sectional view of other embodiment in the longitudinaldirection.

[0203] An inflator housing 12 has an opening portion 14 in one end andthe other end closed. A pressurized medium comprising an inert gas suchas argon, helium or a nitrogen gas is charged into the inner space 16 atthe maximum pressure of about 70,000 kPa. The inflator housing 12 in thewidthwise direction has a circular section, and the opening portion 14is also circular.

[0204] The inflator housing 12 may be formed by utilizing an existentgas cylinder, and it may be produced by swaging a pipe. A pressurizedmedium is charged into an inflator 10 shown in FIG. 1 from an openingportion 14 of the inflator housing 12. In the inflator 10 shown in FIG.4, a pressurized medium is charged from a clearance between a thin holeand a sealing pin 13 inserted therein after a diffuser portion 20 isconnected to the inflator housing 12, and then the inflator housing 12is welded at the sealing pin 13 to be closed completely.

[0205] The diffuser portion 20 is connected in the opening portion 14 ofthe inflator housing 12. An outer shell of the diffuser portion 20 isformed of a diffuser housing 23 and a gas discharging hole 22 fordischarging the pressurized medium outside is provided on the peripheryof the outer shell.

[0206] The inflator housing 12 and the diffuser portion 20 may beconnected by a welding or they may be connected by screwing a male screwportion provided on the periphery of the end portion in the inflatorhousing 12 into a female screw portion provided on the inner peripheralsurface of the end portion in the diffuser portion 20.

[0207] The opening portion 14 of the inflator housing 12 is closed witha rupturable plate 19 in a bowl-like shape, and, before actuation of theinflator, the inner space 16 of the inflator housing 12 is maintained ata high pressure in a hermetic state. A gas discharging hole 22 of thediffuser portion 20 is not closed.

[0208] The bowl-like rupturable plate 19 is made of nickel alloy and hasa thickness of about 0.8 mm or less. A notch in a cross-shape, an X-likeshape, or a Y-like shape or the like is applied to both or either of aconvex surface and concave surface thereof. [Requirement (a)] The depthor a size of the notch is adjusted, with reference to the strength ofthe rupturable plate 19, such that the rupturable plate is not rupturedbefore actuation and that the rupturable plate is ruptured by andetonation wave without making any fragments at actuation.

[0209] An igniter 26 having a priming is provided in the diffuserportion 20 as a rupturing means for the rupturable plate 19. The igniter26 is fitted into the diffuser housing 23 to be mounted to the diffuserportion 20. Numeral 30 denotes a connector, and 32 denotes a lead wirefor connecting to a power supply. The priming containszirconium/potassium perchlorate as a main component in an amount of 280mg or less, and the lower limit of the content is adjusted withreference to the strength of the rupturable plate 19. [Requirement (c)]A gas discharging port 40 is connected to the diffuser portion 20, andthey are connected at a welded portion 44 by welding after the gasdischarging hole 22 of the diffuser portion 20 and a communication hole42 of the gas discharging port 40 are met with each other.

[0210] The gas discharging port 40 is mounted such that the central axis(shown in a dotted chain line in FIG. 1) of the inflator housing 12 andthe central axis (shown in a dotted chain line in FIG. 1) of the gasdischarging port 40 is parallel to each other.

[0211] The gas discharging port 40 comprises a cylindrical member havingone end closed and the other end formed with an opening portion 46, anda filter 48 for removing foreign objects is provided in the vicinity ofthe opening portion 46. [Requirement (b)] An example of the filter 48can be a wire mesh or a laminated body of wire mesh. The filter 48 canbe disposed to cover the communication hole 42 from the flow-path 49 ofthe pressurized medium.

[0212] Next, other embodiment shown in FIG. 2 will be explained. Aninflator 10 shown in FIG. 2 has the same structure as the inflator 10shown in FIG. 1 except for a location of the rupturable plate 19 and amethod of charging the pressurized medium (a sealing pin 13 isprovided).

[0213] In the inflator 10 shown in FIG. 1, the rupturable plate 19 ismounted to the opening portion 14 of the inflator housing 12, but in theinflator 10 shown in FIG. 2, the rupturable plate 19 is mounted to a rimof an opening 21 of the diffuser portion 20. The opening portion 14 ofthe inflator housing 12 and the opening 21 of the diffuser portion 20may be arranged to abut each other. However, as shown in FIG. 3, it isdesirable that they are arranged to obtain a clearance between theopening portion 14 and the rupturable plate 19. The size of theclearance can be adjusted by properly setting the length from theopening 21 to a tip end portion 23 a of the diffuser housing 23 in thediffuser portion 20. In this case, joining by welding can be easilyperformed by abutting the tip end portion 23 a against an expandedportion 15 of the inflator housing 12.

[0214] Next, the operation of the inflator 10 of the present inventionwill be described. At the time of being mounted to a vehicle, theinflator 10 is disposed, being included in a system comprising such asan activation signal-outputting means which comprises an impact sensorand a control unit, and a module case accommodating the above-describedinflator 10 and a curtain air bag. The curtain air bag is connected atthe opening portion 46 of the gas discharging port 40.

[0215] First, when the vehicle receives an impact, the igniter 26 isactivated upon receiving the signal from the impact sensor of thesystem, and the priming is ignited and burnt so that the rupturableplate 19 is ruptured. At this time, since a notch in a cross-shape, aX-like shape or the like is applied to the rupturable plate 19, therupturable plate 19 laps at four portions to open at the cross pointwithout making any fragments.

[0216] Also, when the priming is burnt, black powder of zirconium oxide(ZrO) is inevitably generated. However, the amount ofzirconium-potassium perchlorate is adjusted, so that the amount ofgeneration of the black powder can be limited to the minimum amount. Inthis case, for example, if zirconium-potassium perchlorate is used in anamount of 300 mg or so, the black powder is generated in the air bag insuch an amount as can be distinctly recognized, which makes the occupantuneasy or alarmed, and additionally, there is always a possibility suchthat the air bag may be damaged.

[0217] Since the opening portion 14 is opened due to the rupture of therupturable plate 19, the pressurized medium in the inner space 16 flowsout from the gas discharging hole 22 into the gas discharging port 40via the communication hole 42, and further, it is discharged from theopening portion 46 via the filter 48 to inflate the curtain air bag.

[0218] Furthermore, even if fragments are made at rupture of therupturable plate 19, the fragments are removed by the filter 48 so thatthey are prevented from being discharged into the curtain air bag. Inthis case, part of the black powder is also removed by the filter 48.

[0219] Incidentally, when the inflator of the present invention is usedas an inflator for a side collision, the gas discharging port 40 isunnecessary and the gas discharging hole 22 is connected to an air bagdirectly or via a proper adapter.

[0220] Next, one embodiment of the present invention (I-3) will bedescribed with reference to the drawings. FIG. 1 is a sectional view ofan inflator 10 of the present invention in the longitudinal direction.

[0221] An inflator housing 12 has an opening portion 14 in one end andthe other end closed. A pressurized medium comprising an inert gas suchas argon, helium or a nitrogen gas is charged into the inner space 16 atthe maximum pressure of about 70,000 kPa. The inflator housing 12 in thewidthwise direction has a circular section, and the opening portion 14is also circular.

[0222] The inflator housing 12 may be produced by swaging a pipe, inorder to facilitate manufacturing process, it may be formed by utilizingan existent gas cylinder.

[0223] The diffuser portion 20 is connected in the opening portion 14 ofthe inflator housing 12. An outer shell of the diffuser portion 20 isformed of a diffuser housing 23 and a gas discharging hole 22 fordischarging the pressurized medium outside is provided on the peripheryof the outer shell.

[0224] The opening portion 14 of the inflator housing 12 is closed witha rupturable plate 19 in a bowl-like shape which is mounted via anannular member 18, and, before actuation of the inflator, the innerspace 16 of the inflator housing 12 is maintained at a high pressure ina hermetic state. A gas discharging hole 22 of the diffuser portion 20is not closed.

[0225] An igniter 26 having a priming is provided in the diffuserportion 20 as a rupturing means for the rupturable plate 19. The igniter26 is fitted into the diffuser housing 23 to be mounted to the diffuserportion 20. Numeral 30 denotes a connector, and 32 denotes a lead wirefor connecting to a power supply.

[0226] A gas discharging port 40 is connected to the diffuser portion20, and they are connected at a welded portion 44 by welding after thegas discharging hole 22 of the diffuser portion 20 and a communicationhole 42 of the gas discharging port 40 are met with each other.

[0227] The gas discharging port 40 is mounted such that the central axis(shown in a dotted chain line in FIG. 1) of the inflator housing 12 andthe central axis (shown in a dotted chain line in FIG. 1) of the gasdischarging port 40 is parallel to each other.

[0228] The gas discharging port 40 comprises a cylindrical member havingone end closed and the other end formed with an opening portion 46, anda filter 48 for removing foreign objects is provided in the vicinity ofthe opening portion 46. An example of the filter 48 can be a wire meshor a laminated body of wire mesh. A location of the filter 48 is notparticularly limited if foreign objects can be removed from thedischarging pressurized medium. For example, the filter 48 can bedisposed to cover the communication hole 42 from the flow-path 49 of thepressurized medium.

[0229] Part of a manufacturing method of the inflator 10 will beexplained. As shown in FIGS. 5 and 6, the rupturable plate 19 is weldedand fixed at an opening of the annular member 18, and the annular member18 is fixed by resistance-welding after the annular member 18 is fittedinto the opening portion 14 of the inflator housing 12. Inert gas(pressurized medium) is charged from a little clearance remainingbetween the annular member 18 and the opening portion 14 after theannular member 18 is fitted but before the resistance-welding, andthereafter the resistance-welding is performed. FIG. 7 is a plan view ofthe annular member 18.

[0230] The inflator housing 12 and the diffuser portion 20 is byscrewing a male screw portion (or female screw portion) provided on theouter surface of the end portion in the inflator housing 12 into afemale screw portion (or male screw portion) provided on the innersurface of the end portion in the diffuser portion 20.

[0231] Next, the operation of the inflator 10 of the present inventionwill be described. At the time of being mounted to a vehicle, theinflator 10 is disposed, being included in a system comprising such asan activation signal-outputting means which comprises an impact sensorand a control unit, and a module case accommodating the above-describedinflator 10 and a curtain air bag. The curtain air bag is connected atthe opening portion 46 of the gas discharging port 40.

[0232] First, when the vehicle receives an impact, the igniter 26 isactivated upon receiving the signal from the impact sensor of thesystem, and the priming is ignited and burnt so that the rupturableplate 19 is ruptured.

[0233] Since the opening portion 14 is opened due to the rupture of therupturable plate 19, the pressurized medium in the inner space 16 flowsout from the gas discharging hole 22 into the gas discharging port 40via the communication hole 42, and further, it is discharged from theopening portion 46 via the filter 48 to inflate the curtain air bag.

[0234] In the series of operations, when the pressurized medium isdischarged from the opening portion 46 of the gas discharging port 40,the flow direction of the pressurized medium is coincident with thedirection of the center axis of the gas discharging port 40 so that theflow direction is coincident with the direction of the center axis ofthe inflator housing 12. Thereby, the curtain air bag connected to theopening portion 46 of the gas discharging port 40 inflates and developsin the same direction as the flow direction of the pressurized medium.

[0235] Furthermore, if fragments are made at rupture of the rupturableplate 19, the fragments are removed by the filter 48 so that they areprevented from being discharged into the curtain air bag.

[0236] Incidentally, if the inflator of the present invention is used asa inflator for a side collision, the gas discharging port 40 isunnecessary and the gas discharging hole 22 is connected with an air bagdirectly or via a proper adapter.

PREFERRED EMBODIMENT OF THE INVENTION (II)

[0237] One embodiment of the present invention will be described belowwith reference to the drawings. FIG. 8 is a sectional view of aninflator 310 of the present invention in the longitudinal direction,FIG. 9 is a sectional view of an adapter which is an attachment mountedto the inflator shown in FIG. 8, FIG. 10 is a sectional view of aninflator 310 of other embodiment in the longitudinal direction, andFIGS. 11 and 12 are partially sectional views of inflators 310 of otherembodiments in the longitudinal directions.

[0238] First, an embodiment shown in FIG. 8 will be explained. Aninflator housing 312 has an opening portion 314 in one end and the otherend closed. A pressurized medium comprising an inert gas such as argon,helium or a nitrogen gas is charged into the inner space 316 at themaximum pressure of about 70,000 kPa. The inflator housing 312 in thewidthwise direction has a circular section, and the opening portion 314is also circular.

[0239] The inflator housing 312 may be formed by utilizing an existentgas cylinder, and it may be produced by swaging a pipe or applying apipe spinning. A pressurized medium is charged into an inflator 310shown in FIG. 8 from an opening portion 314 of the inflator housing 312.In the inflator 310 shown in FIG. 10, a pressurized medium is chargedfrom a clearance between a thin hole and a sealing pin 313 insertedtherein after a diffuser portion 320 is connected to the inflatorhousing 312, and then the inflator housing 312 is welded at the sealingpin 313 to be closed completely.

[0240] The diffuser portion 320 is connected in the opening portion 314of the inflator housing 312. An outer shell of the diffuser portion 320is formed of a diffuser housing 323 and a gas discharging hole 322 fordischarging the pressurized medium outside is provided on the peripheryof the outer shell.

[0241] The inflator housing 312 and the diffuser portion 320 may beconnected by a welding or they may be connected by screwing a male screwportion provided on the periphery of the end portion in the inflatorhousing 312 into a female screw portion provided on the inner peripheralsurface of the end portion in the diffuser portion 320.

[0242] The opening portion 314 of the inflator housing 312 is closedwith a rupturable plate 319 in a bowl-like shape, and, before actuationof the inflator, the inner space 316 of the inflator housing 312 ismaintained at a high pressure in a hermetic state. A gas discharginghole 322 of the diffuser portion 320 is not closed.

[0243] An igniter 326 having a priming is provided in the diffuserportion 320 as a rupturing means for the rupturable plate 319. Theigniter 326 is fitted into the diffuser housing 323 to be mounted to thediffuser portion 320. Numeral 330 denotes a connector, and 332 denotes alead wire for connecting to a power supply.

[0244] A gas discharging port 340 is connected to the diffuser portion320, and they are connected at a welded portion 344 by welding after thegas discharging hole 322 of the diffuser portion 320 and a communicationhole 342 of the gas discharging port 340 are met with each other.

[0245] The gas discharging port 340 is mounted such that the centralaxis (shown in a dotted chain line in FIG. 8) of the inflator housing312 and the central axis (shown in a dotted chain line in FIG. 8) of thegas discharging port 340 is parallel to each other.

[0246] The gas discharging port 340 comprises a cylindrical memberhaving one end closed and the other end formed with an opening portion346, and a filter 348 for removing foreign objects is provided in thevicinity of the opening portion 346. An example of the filter 348 can bea wire mesh or a laminated body of wire mesh. A location of the filter348 is not particularly limited if foreign objects can be removed fromthe discharging pressurized medium. For example, the filter 348 can bedisposed to cover the communication hole 342 from the flow-path 349 ofthe pressurized medium.

[0247] An adapter 350 can be mounted to the opening portion 346 of thegas discharging port 340 to be attached or removed optionally at storageand transportation. The adapter 350 is a disk-like member or acylindrical member, it has therein a concave portion 352 to receive anend portion of the opening portion in the gas discharging port 340 andanother concave portion having a smaller diameter than that of theconcave portion 352, and a plurality of ejecting holes 356 ofthrough-holes piercing to an outer peripheral surface are provided inthe concave portion 354. Incidentally, the adapter 350 can be made of anelastic member such as a rubber, plastics or the like in order toenhance an connecting with the gas discharging port 340, and anunillustrated fastening member such as a screw or the like can furtherbe provided.

[0248] In this embodiment, the outflow rate of the pressurized medium iscontrolled by setting the opening area of the gas discharging hole 322to preferably 5 to 500 mm², more preferably 10 to 250 mm² and furtherpreferably 12 to 113 mm². Incidentally, a method for measuring apressure loss in the filter can be implemented on the basis of thedescription from line 17 on column 19 to line 43 on column 20 and FIGS.8 and 9 of JP-B No. 2926040.

[0249] Next, other embodiment shown in FIG. 10 will be described. Aninflator 310 shown in FIG. 10 has the same structure as the inflator 310shown in FIG. 8 except for a location of a rupturable plate 319 and amethod of charging a pressurized medium (the sealing pin 313 isprovided).

[0250] In the inflator 310 shown in FIG. 8, the rupturable plate 319 ismounted to the opening portion 314 of the inflator housing 312, but inthe inflator 310 shown in FIG. 10, the rupturable plate 319 is mountedto a rim of an opening 321 of the diffuser portion 320. The openingportion 314 of the inflator housing 312 and the opening 321 of thediffuser portion 320 may be arranged to abut each other. However, asshown in FIG. 10, it is desirable that they are arranged to obtain aclearance between the opening portion 314 and the rupturable plate 319.The size of the clearance can be adjusted by properly setting the lengthfrom the opening 321 to a tip end portion 323 a of the diffuser housing323 in the diffuser portion 320. In this case, joining by welding can beeasily performed by abutting the tip end portion 323 a against anexpanded portion 315 of the inflator housing 312.

[0251] Next, the operation of the inflator 310 shown in FIGS. 8 to 10will be described. At the time of being mounted to a vehicle, theinflator 310 is disposed, being included in a system comprising such asan activation signal-outputting means which comprises an impact sensorand a control unit, and a module case accommodating the above-describedinflator 310 and a curtain air bag. The curtain air bag is connected atthe opening portion 346 of the gas discharging port 340.

[0252] First, when the vehicle receives an impact, the igniter 326 isactivated upon receiving the signal from the impact sensor of thesystem, and the priming is ignited and burnt so that the rupturableplate 319 is ruptured.

[0253] Since the opening portion 314 is opened due to the rupture of therupturable plate 319, the pressurized medium in the inner space 316flows out from the gas discharging hole 322 into the gas dischargingport 340 via the communication hole 342, and further, it is dischargedfrom the opening portion 346 via the filter 348 to inflate the curtainair bag.

[0254] In the series of operations, when the pressurized medium isdischarged from the opening portion 346 of the gas discharging port 340,the flow direction of the pressurized medium is coincident with thedirection of the center axis of the gas discharging port 340 so that theflow direction is coincident with the direction of the center axis ofthe inflator housing 312. Thereby, the curtain air bag connected to theopening portion 346 of the gas discharging port 340 inflates anddevelops in the same direction as the flow direction of the pressurizedmedium.

[0255] Furthermore, if fragments are made at rupture of the rupturableplate 319, the fragments are removed by the filter 348 so that they areprevented from being discharged into the curtain air bag.

[0256] Also, when a fire breaks out at a time of storage, transportationor the like before the air bag apparatus is mounted on a vehicle andthen the igniter 326 is actuated erroneously and the rupturable plate319 is ruptured, the pressurized medium flows out from the openingportion 346 of the gas discharging port 340, and consequently thecurtain inflator 310 is ejected like a rocket utilizing the outflow ofthe pressurized medium as a thrust, which is very dangerous. However, ifthe adapter 350 is attached to the opening portion 346 of the gasdischarging port 340, the pressurized medium flows from the plurality ofejecting holes 356 in the circumferential direction, a danger at theworst can be avoided.

[0257] Next, other embodiment shown in FIG. 11 will be explained. Commonnumerals in FIGS. 8 and 10 denote identical parts. Incidentally, theadapter 350 shown in FIG. 9 can be attached to the inflator 310 shown inFIG. 11.

[0258] In the inflator 310 shown in FIG. 11, a gas discharging port 340is mounted on an extension of the central line of an opening portion 314of an inflator housing 312. For this reason, after a rupturable plate319 is ruptured at actuation, the pressurized medium flows out from anopening portion 346 of the gas discharging port 340 via the openingportion 314 of the inflator housing 312, an inner space 320 a of thediffuser portion 320 and a gas discharging port 340 (flow path 349 ofthe pressurized medium) without changing the outflow direction of thepressurized medium.

[0259] An igniter 326 which is a rupturing means for the rupturableplate 319 provided in the diffuser portion 320 is arranged to face theinner space 320 a of the diffuser portion 320 and such that the centralaxis of the igniter 326 is inclined to the central line of therupturable plate 319 (coincident with the central line of the openingportion 314, the flow direction of the pressurized medium, the centralaxis of the inner space 320 a of the diffuser portion 320, and thecentral axis of the gas discharging port 340). It is preferable that anangle (θ) formed by the central axis of the igniter 326 and the centralline of the rupturable plate is acute, more preferably, 10 to less than90°, further preferably, 40 to 50°.

[0260] Next, the operation of the inflator 310 shown in FIG. 11 will beexplained. When the vehicle received an impact, the igniter 326 isactuated upon receiving the signal form the impact sensor, and thepriming is ignited and burnt so that rupturable plate 319 is ruptured.At this time, since the igniter 326 and the rupturable plate 319 arearranged to have the angle θ, the rupture can securely be performed.

[0261] Since the opening portion 314 opens by the rupture of therupturable plate 319, the pressurized medium in the inner space 316passes through the inner space 320 a of the diffuser portion 320 andthrough the filter 348 and the flow path 349, and then flows out fromthe opening portion 346 to inflate the curtain air bag.

[0262] In this series of operations, the pressurized medium does notchange the outflow direction thereof, so that the curtain air bagconnected to the opening portion 346 of the gas discharging port 340inflates and develops in the same direction as the outflow direction ofthe pressurized medium.

[0263] Next, other embodiment shown in FIG. 12 will be explained. Commonnumerals in FIGS. 8 and 10 denote identical parts. Incidentally, theadapter shown in FIG. 9 is also attached to the inflator 310 shown inFIG. 12.

[0264] In the inflator shown in FIG. 12, like the inflator 310 shown inFIG. 11, the gas discharging port 340 is mounted on an extension of thecentral line of the opening portion 314 of the inflator housing 312. Forthis reason, after a rupturable plate 319 is ruptured at actuation, thepressurized medium flows out from an opening portion 346 of the gasdischarging port 340 via the opening portion 314 of the inflator housing312, an inner space 320 a of the diffuser portion 320 and a gasdischarging port 340 (flow path 349 of the pressurized medium) withoutchanging the outflow direction of the pressurized medium.

[0265] An igniter 326 which is a rupturing means for the rupturableplate 319 provided in the diffuser portion 320 is arranged facing theinner space 320 a of the diffuser portion 320 and to crossperpendicularly to the central line of the rupturable plate 319.

[0266] The rupturable plate 319 is a cylindrical member disposed in theinner space 320 a of the diffuser portion 320 and having one end closedand the other end open. And it closes the inner space 320 a of theoutflow path of the pressurized medium with a closed end 319 a and aperipheral face 319 b. Also, part of the peripheral face 319 b facesoppositely an igniter 326 via an igniting hole 327. Here, the size (d₁)of the outer diameter of the cylindrical rupturable plate 319 and thesize (d₂) of the inner diameter of the inner space 320 a of the diffuserportion 320 are incident with each other or d₁ is slightly larger thand₂ (d₁>d₂). By setting the sizes to d₁>d₂, the opening portion 314 issecurely closed and the outflow of the pressurized medium can beprevented from being discharged.

[0267] Furthermore, even when d₁ is smaller than d₂, a secure sealingcan be achieved by welding and fixing a flange (an opening rim of therupturable plate 319) of the rupturable plate 319) to the diffuserportion 320 abutting thereon. Naturally, when d₁ is larger than d₂, awelding can also be performed in the same manner. As a welding method, alaser welding, a resistance-welding, an electron beam welding or thelike can be employed.

[0268] Next, the operation of the inflator 310 shown in FIG. 12 will beexplained. When a vehicle receive an impact, the igniter 326 isactivated upon receiving a signal from an impact sensor, and the primingis ignited and burnt so that a flame is ejected from the igniting hole327 to rupture part of the peripheral surface 319 b of the rupturableplate 319 facing oppositely the igniting hole 327. Due to the rupture,the rupturable plate 319 is deformed such that the closed end 319 a lapstowards the filter 348.

[0269] Since the opening portion 314 opens due to the rupture of therupturable plate 319, the pressurized medium in the inner space 316passes through the inner space 320 a of the diffuser portion 320 andthrough the filter 348 and the flow path 349, and flows out from theopening portion 346 to inflate the curtain air bag.

[0270] In this series of operations, the pressurized medium does notchange the outflow direction thereof, and the curtain air bag connectedto the opening portion 346 of the gas discharging port 340 inflates anddevelops in the same direction as the outflow direction of thepressurized.

[0271] Next, other embodiment shown in FIG. 13 will be explained. FIG.13 is a sectional view of an inflator 100 of the present invention inthe longitudinal direction.

[0272] An inflator housing 112 has an opening portion 114 at one end andthe other end closed, and a pressurized medium comprising an inert gasis charged into the inner space 116 at the maximum pressure of 35,000kPa. The inflator housing 112 in the widthwise direction has a circularsection, and the opening portion 114 is circular similarly. The inflatorhousing 112 is manufactured by swaging method or the spinning method inthe same manner as that shown in FIG. 8 and it is charged with thepressurized medium. Numeral 140 denotes a state where a thin hole isclosed by a welding.

[0273] A diffuser portion 120 is fixed to the opening portion 114 of theinflator housing 112 at a joining portion 118 by a welding. The diffuserportion 120 has a plurality of gas discharging holes 122 for dischargingthe pressurized medium flowing from the opening portion 114 atactuation, and has an annular filter 124 made of a plain-stitched wiremesh or the like and arranged to cover the plurality of gas dischargingholes 122 from the inside. An annular space 123 is provided between theplurality of gas discharging hole 122 and the annular filter 124, andthe pressurized medium is discharged from the gas discharging hole 122after passing through the annular filter 124 and the annular space 123.As illustrated, since the width of the annular filter 124 is made largerthan the width of the annular space 123, and the sectional area in theradial direction of the annular space 123 is made larger than the totalopening area of the gas discharging hole 122, so that the outflow amountof the pressurized medium is controlled by the gas discharging hole 122.

[0274] The opening portion 114 of the inflator housing 112 is closedwith the rupturable plate 119, and, before actuation, the inner space116 of the inflator housing 112 is maintained at a high pressure in ahermetic state. The gas discharging hole 122 is not closed, ventilatingwith the outside.

[0275] An igniter 126 including a priming is provided in the diffuserportion 120 as the rupturing means for the rupturable plate 119. Theigniter 126 is fitted into a collar 128 and mounted to the diffuserportion 120, and it is fixed by crimping an end portion 129 of thediffuser portion 120. Numeral 130 denotes a conductive pin forelectrifying the igniter 126, 131 denotes a O-ring, and 132 shown with abroken line denotes a connector for connection to a power supply at atime of mounting to a vehicle.

[0276] When the inflator 100 is activated, the pressurized medium flowsfrom approximately the whole surface of the filter 124 to the annularspace 123, and is discharged from the gas discharging hole 122. For thisreason, since fragments of the rupturable plate 119 are captured onapproximately the whole surface of the annular filter 124, the outflowamount of the pressurized medium is prevented from being decreased, andsince the pressurized medium passes through the whole filter, a filtereffect (filtering effect) is improved.

[0277] Next, other embodiment shown in FIG. 14 will be explained. FIG.14 is a partially sectional view of an inflator 200 of the presentinvention in the longitudinal direction.

[0278] An inflator housing 212 has an opening portion 214 at one end andthe other end closed. A pressurized medium comprising an inert gas suchas argon, helium or the like or a nitrogen gas is charged into an innerspace 216 at the maximum pressure of about 70,000 kPa. The inflatorhousing 212 in the widthwise direction has a circular section, and theopening portion 14 is also circular. The inflator housing 212 ismanufactured in the same manner as that in FIG. 8 and charged with thepressurized medium.

[0279] A diffuser portion 220 is connected to the opening portion 214 ofthe inflator housing 212, and the diffuser portion 220 has a first gasdischarging hole 222 for discharging the pressurized medium outside. Theinflator housing 212 and the diffuser portion 220 can be connected toeach other by a welding or screwing.

[0280] The outflow path 218 of the pressurized medium between theopening portion 214 of the inflator housing 212 and the diffuser portion220 is closed with a bowl-like rupturable plate 219, and, beforeactuation, the inner space 216 in the inflator housing 212 is maintainedat a high pressure in a hermetic state. In FIG. 14, the rupturable plate219 is attached to the diffuser portion 220, but it may be attached tothe opening portion 214 of the inflator 212. The first gas discharginghole 222 of the diffuser portion 220 is not closed.

[0281] An igniter 226 having a priming is provided in the diffuser 220as a rupturing means for the rupturable plate 219. The igniter 226 ismounted after the inflator housing 212 and the diffuser portion 220 areconnected to each other. The igniter 226 is fitted from one end openingof the diffuser portion 220 towards the rupturable plate, and afterfitted, it is fixed by crimping a peripheral edge 228 of the one endopening in the diffuser portion 220. Numeral 230 denotes a connector.

[0282] A gas discharging port 240 is connected to the diffuser portion220, where the both are connected by press-fitting an inflow portion 242of the gas discharging port 240 for the pressurized medium into thefirst gas discharging hole 222 of the diffuser portion 220. At thistime, the diameter of the inflow portion 242 of the gas discharging port240 is set to be slightly smaller than the diameter of the first gasdischarging hole 222 of the diffuser portion 220.

[0283] The gas discharging port 240 comprises a main body portion 240 ahaving one end closed (a closed end surface 262), the other end open anda flange portion 263, and an adapter portion 240 b. These portions areconnected to each other by engaging the flange portion 263 of the mainbody portion 240 a with the inside of the adapter portion 240 b, orcrimping an end portion of the adapter 240 b after fitting.Additionally, connection can be made by applying a resistance-welding.Incidentally, the gas discharging port 240 can have a structure suchthat the main body portion 240 a and the adapter portion 240 b areintegrated with each other.

[0284] The adapter portion 240 b and the diffuser portion 220 areconnected to each other at a welded portion 235 by a resistance-welding.At this time, after the adapter portion 240 b (inflow portion 242) andthe diffuser portion 220 are resistance-welded, the main body portion240 a can be connected. Alternatively, after the main body portion 240 aand the adapter portion 240 b are connected to each other, the adapterportion 240 b and the diffuser portion 220 can be resistance-welded.

[0285] A plurality of opening portions (a second gas discharging hole)260 is provided in a side surface of the main body portion 240 a, and ascreen 248 having a plurality of outflow holes 249 through which allowsthe pressurized medium to pass for removing foreign objects is arrangedin the inside thereof. A hole diameter of the outflow holes 249 can beselected from the numerical range of 0.5 to 2.0 mm.

[0286] At least two openings among the plurality of opening portions 260are positioned symmetrical to each other or approximately symmetrical toeach other in the widthwise direction. For example, six opening portions260 are provided and they are arranged in the circumferential directionat equal intervals.

[0287] The screen 248 can comprise a cylindrical member formed of onelayer or multiple layers of a punched metal, a plain-stitched wire meshor a similar member, and the screen 248 is arranged such that the axialdirection of the screen 248 and the axial direction of the gasdischarging port 240 (the main body portion 240 a) are coincident witheach other. Outflow holes 249 are provided on the whole surface of thescreen 248, but only outflow holes facing the opening portion 260discharge the pressurized medium, functioning as a remover of foreignobjects.

[0288] The screen 248 can be fixed, for example, by the followingmethods. After a cylindrical punched metal having substantially the samediameter as the inner diameter of the main body portion 240 a isinserted and arranged inside the main body portion 240 a, an embossingis performed from the outside of the outer surface of the main bodyportion 240 a towards the inside thereof to provide convex portions atabout three positions, so that the screen 248 can be supported andfixed. Also, the punched metal or the like is rolled tightly to form acylinder having a diameter sufficiently smaller than the inner diameterof the main body portion 240 a and it can be fixed by utilizing afunction of the tightly rolled punched metal or the like which bulges inthe radial direction to press the inner wall of the main body portion240 a.

[0289] A convex portion 264 and a groove portion (concave portion) 261provided continuously in the circumferential direction or at intervals(desirably, continuously) are formed on the main body portion 240 a inthe adapter 240 b side.

[0290] The convex portion 264 has a flat surface at top and a screwportion (a male screw portion or a female screw portion) can beprovided, as required, and it is provided in the vicinity of the openingportion 260. The convex portion 264 is useful when the inflator 200 isconnected to the air bag at the gas discharging port 240. The height ofthe convex portion 264 in the radial direction and the length thereof inthe axial direction can be determined with reference to the connectivity(connection strength, workability or the like) with the air bag.

[0291] When the air bag apparatus is assembled, the groove portion 261functions such that, after the main body portion 240 a is covered withthe air bag, the air bag can be fastened at the groove portion 261 sothat the both can firmly be joined and the air bag can be prevented fromfalling off. The depth of the groove portion 261 in the radial directioncan be determined with reference to the connectivity (connectionstrength, workability or the like) with the air bag.

[0292] In the inflator 200, the outflow amount of the pressurized mediumcan be controlled at a desired portion by adjusting the magnituderelationship among the diameter (opening area) of the outflow path 218of the pressurized medium, the diameter (total opening area) of thefirst gas discharging hole 222, the diameter (total opening area) of thesecond gas discharging hole 260, the total opening area of the outflowhole 249 of the screen 248 or the like. For example, by minimizing theopening area of the outflow path 218 of the pressurized medium, theoutflow amount of the pressurized medium can be controlled at theoutflow path 218.

[0293] Next, with reference to FIG. 14, an aspect suitable forconnecting the air bag and the inflator 200 to each other will bedescribed.

[0294] A male screw portion is provided on the top surface of the convexportion 264 provided on the gas discharging port 240, and a mouthpiecehaving a female screw (has the same number of threads as that of themale screw portion) on the inner surface is attached to an opening ofthe air bag. The both are connected by screwing the male screw portionof the convex portion 264 into the female screw portion of themouthpiece. Then, a distance L₁ from an end (an end nearer to the grooveportion 261) of the convex portion 264 to an end (an end nearer to theclosed end face 262) of the opening portion 260 and the length L₂ of themouthpiece are set to be equal to each other. For this reason, when theair bag is mounted to the gas discharging port 240, a clearance(preferably, of 1 to 5 mm, more preferably, of 1.2 to 3 mm) serving asan outflow path of the pressurized medium is secured between the openingportion 260 and the inner surface of the mouthpiece, so that theinflation of the air bag can rapidly and securely be performed.Incidentally, as mentioned above, as long as the pressurized medium isejected smoothly at the initial stage of actuation, the flow path of thepressurized medium thereafter is secured, so that L₁>L₂ may be employed.

[0295] It is desirable that the sectional area of the clearance (an areashown as A in FIG. 15) defined by a difference between the sectionalarea of the mouthpiece in the widthwise direction and the sectionalarea, in the widthwise direction, in the insertion portion reaching theconvex portion of the gas discharging port main body portion 240 a isset to be larger than the total opening area of the outflow hole 249 ofthe screen 248 arranged at the gas discharging port 240 or the totalopening area of the first gas discharging hole 222 arranged in thediffuser portion 220. By achieving such a relationship, the outflowamount of the pressurized medium can be controlled by the screen 248 orthe first gas discharging hole 222. The opening area of the gasdischarging hole 222 can be selected from the range of 15 to 30 mm², andthe total opening area of the outflow hole 249 can be selected from therange of 30 to 60 mm².

[0296] In case that the inflator of the present invention is used as aninflator for a side collision, the gas discharging port becomesunnecessary and the air bag is connected to the gas discharging holedirectly or via a suitable adapter.

PREFERRED EMBODIMENT OF THE INVENTION (III)

[0297] A filter means for an inflator (hereinafter, referred to as “afilter means”) of the present invention will be explained with referenceto the drawings. FIG. 16 is a plan view of a filter means, FIG. 17 is asectional view of the filter means shown in FIG. 16 in the diametricaldirection, and FIG. 18 is a plan view of a disk-shaped supporting bodyconstituting the filter means.

[0298] A filter means 400 comprises a disk-shaped supporting body 402and a filter member 404 covering one surface or both surfaces of thedisk-shaped supporting body 402. The disk-shaped supporting body 402 hasa required number (7 in the drawing) of through holes 403, and gas flowsout through these through holes 403.

[0299] A screw portion 402 a for mounting inside the inflator to beattached or removed optionally is provided on an outer peripheralsurface of the disk-shaped supporting body 402, and the screw portion402 a is a male screw portion (or female screw portion) to be screwed inthe inflator.

[0300] The filter member 404 comprises a punched metal or lath metalmade of a metal such as stainless steel, and it is fixed to one surfaceof the disk-shaped supporting body 402 at a plurality of positions(shown as numeral 405 in drawing) by spot welding. The mesh of sieve ofthe filter member 404 can properly be set in the range developing afunction as a filter for removing foreign objects, according to theinflator to be applied. In case of a mesh of sieve of a regular square,one side is preferably 0.4 to 2.0 mm, more preferably, 0. 6 to 1.0 mm,further preferably 0.6 to 0.9 mm.

[0301] When both surfaces of the disk-shaped supporting body 402 arecovered with the filter members 404, the meshes of sieve of the filtermembers can be set to be identical or they can be set to be differentfrom each other.

[0302] If it is necessary to cool the pressurized medium duringactuation, a cooling function can be given. For example, a method ofmaking the disk-shaped supporting body 402 of a wire mesh member with alarge specific surface area, a method of making the disk-shapedsupporting body 402 of a material (aluminum, silver or the like) with alarge heat conductivity, a method of combining the above two methods orthe like can be employed for the filter means 400 having a coolingfunction.

[0303] Next, the inflator in which the filter means 400 is disposed willbe explained based on the drawings. FIG. 19 is a sectional view of aninflator 510 of the present invention in the longitudinal direction anda sectional view of an adapter 550 mounted to the inflator 510 of thepresent invention in the diametrical direction.

[0304] An inflator housing 512 has an opening 514 at one end and theother end closed. A pressurized medium comprising an inert gas such asargon, helium or the like or a nitrogen gas is charged into the innerspace 516 at the maximum pressure of about 70,000 kPa. The inflatorhousing 512 in the widthwise direction has a circular section, and theopening 514 is also circular.

[0305] The inflator housing 512 may be formed by utilizing an existentgas cylinder, and it may be produced by swaging a pipe. After a diffuserportion 520 is connected to the inflator housing 512, a pressurizedmedium is charged via a clearance between a thin hole and a sealing pin513 inserted therein and then the inflator housing 12 is welded at aportion of the sealing pin 513 to be closed completely.

[0306] The inflator housing 512 and the diffuser portion 520 may beconnected by a welding or they may be connected by screwing a male screwportion provided on the periphery of the end portion in the inflatorhousing 512 into a female screw portion provided on the inner peripheralsurface of the end portion in the diffuser portion 520.

[0307] The opening portion 514 of the inflator housing 512 is closedwith a rupturable plate 519 in a bowl-like shape, and, before actuationof the inflator, the inner space 516 of the inflator housing 512 ismaintained at a high pressure in a hermetic state. A gas discharginghole 522 of the diffuser portion 520 is not closed.

[0308] An igniter 526 having a priming is provided in the diffuserportion 520 as a rupturing means for the rupturable plate 519. Theigniter 526 is fitted into the diffuser housing 523 to be mounted to thediffuser portion 520. Numeral 530 denotes a connector, and 532 denotes alead wire for connecting to a power supply.

[0309] A gas discharging port 540 is connected to the diffuser portion520, and they are connected at a welded portion 544 by welding after thegas discharging hole 522 of the diffuser portion 520 and a communicationhole 542 of the gas discharging port 540 are met with each other. Also,the diffuser portion and the gas discharging port can be connected byfastening the both from the outside with a fastening means such as ametal band.

[0310] The gas discharging port 540 is mounted such that the centralaxis (shown in a dotted chain line in FIG. 16) of the inflator housing512 and the central axis (shown in a dotted chain line in FIG. 16) ofthe gas discharging port 540 is parallel to each other. The gasdischarging port 540 comprises a cylindrical member having one endclosed and the other end formed with an opening portion 546, and aninner peripheral surface 541 is provided with a female screw portion (ora male screw portion).

[0311] Filter means 400 a and 400 b constituting the filter means 400for removing foreign objects shown in FIGS. 16 and 17 are arranged inthe gas discharging port 540. It is preferable, in view of weightreduction of whole the inflator, that the number of filter means to bedisposed is one or two, but three or four or more filter means can bedisposed.

[0312] Two filter means 400 a and 400 b are disposed at interval, butthey may be disposed to contact with each other. The mesh of sieve ofthe filter means 400 a is set to be larger than that of the filter means400 b, relatively large foreign objects are first removed by the filtermeans 400 a and the relatively smaller remaining foreign objects areremoved by the filter means 400 b. Incidentally, if filter means 400provided with the filter members 404 on both sides is used, the filtermeans is arranged such that the surface of the filter member 404 with alarger mesh of sieve is positioned in the gas discharging hole 522 sideand the surface of the filter member 404 with a smaller mesh of sieve ispositioned in the opening portion 546 side.

[0313] The filter means 400 a and 400 b can be madeattachable/detachable by screwing the filter means in the gasdischarging port 540 using a rod-like jig, and can be arranged movablyat a desired position. As to the orientation of disposing the filtermeans 400, the filter means 400 is desirably disposed such that thepressurized medium flows out in the arrow direction in FIG. 17.

[0314] An adapter 550 can be mounted to the opening portion 546 of thegas discharging port 540 to be attached or removed optionally at storageand transportation. The adapter 550 is an annular plate member or acylindrical member, as shown in FIG. 20, it has therein a concaveportion 552 to receive an end portion of the opening portion in the gasdischarging port 540 and another concave portion having a smallerdiameter than that of the concave portion 552, and a plurality ofejecting holes 556 of through-holes piercing to an outer peripheralsurface are provided in the concave portion 554. Incidentally, theadapter 550 can be made of an elastic member such as a rubber, plasticsor the like in order to enhance an connecting with the gas dischargingport 540, and an unillustrated fastening member such as a screw or thelike can further be provided.

[0315] Next, the operation of the inflator 510 will be described. At thetime of being mounted to a vehicle, the inflator 510 is disposed, beingincluded in a system comprising such as an activation signal-outputtingmeans which comprises an impact sensor and a control unit, and a modulecase accommodating the above-described inflator 510 and a curtain airbag. The curtain air bag is connected at the opening portion 546 of thegas discharging port 540.

[0316] First, when the vehicle receives an impact, the igniter 526 isactivated upon receiving the signal from the impact sensor of thesystem, and the priming is ignited and burnt so that the rupturableplate 519 is ruptured. At this time fragments with different sizes canbe made.

[0317] Since the opening portion 514 is opened due to the rupture of therupturable plate 519, the pressurized medium in the inner space 516flows out from the gas discharging hole 522 into the gas dischargingport 540 via the communication hole 542, and further, it is dischargedfrom the opening portion 546 via the filter members 400 a and 400 b toinflate the curtain air bag. At this time, relatively larger fragmentsare first removed by the filter means 400 a with large meshes of sieveand then, relatively smaller fragments are removed by the filter meanswith small meshes of sieve. When the arrangement of the filter means 400a and 400 b is reversed, the filter means 400 a with small meshes ofsieve tends to get clogged, and thereby a smooth outflow of thepressurized medium may be blocked.

[0318] In the series of operations, when the pressurized medium isdischarged from the opening portion 546 of the gas discharging port 540,the flow direction of the pressurized medium is coincident with thedirection of the center axis of the gas discharging port 540 so that theflow direction is coincident with the direction of the center axis ofthe inflator housing 512. Thereby, the curtain air bag connected to theopening portion 546 of the gas discharging port 540 inflates anddevelops in the same direction as the flow direction of the pressurizedmedium. Furthermore, if fragments are made at rupture of the rupturableplate 519, the fragments are removed by the filter means 400 a and 400 bso that they are prevented from being discharged into the curtain airbag.

[0319] Also, when a fire breaks out at a time of storage, transportationor the like before the air bag apparatus is mounted on a vehicle andthen the igniter 526 is actuated erroneously and the rupturable plate519 is ruptured, the pressurized medium flows out from the openingportion 546 of the gas discharging port 540, and consequently thecurtain inflator 510 is ejected like a rocket utilizing the outflow ofthe pressurized medium as a thrust, which is very dangerous. However, ifthe adapter 550 is attached to the opening portion 546 of the gasdischarging port 540, the pressurized medium flows from the plurality ofejecting holes 556 in the circumferential direction, a danger at theworst can be avoided.

[0320] Incidentally, if the inflator of the present invention is used asa inflator for a side collision, the gas discharging port 540 isunnecessary and the gas discharging hole 522 is connected with an airbag directly or via a proper adapter.

1. An inflator comprising an inflator housing in which a pressurizedmedium is charged and one end is provided with an opening portion, adiffuser portion which is connected to the opening portion of theinflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at a time of actuation, a rupturable plate closing anoutflow path for the pressurized medium between the diffuser portion andthe opening portion of the inflator housing, and an igniter whichincludes a priming for rupturing the rupturable plate with an detonationwave and is provided in the diffuser portion, wherein one or combinationof at least two requirements selected from the following requirements(a) to (d) are provided: (a) the igniter has a charge holder for givingdirectivity to detonation waves generated due to combustion of thepriming. (b) the igniter has a cup arranged to include at least apriming therein and the cup has a fragile portion in a portion facingthe rupturable plate. (c) an explosive is attached on the surface of therupturable plate. (d) the rupturable plate has a fragile portion.
 2. Aninflator according to claim 1, wherein the charge holder meeting therequirement (a) is arranged to surround at least a priming of theigniter and a side of the holder which faces the rupturable plate isopen.
 3. An inflator according to claim 1, wherein the fragile portionmeeting the requirement (b) is formed by providing a notch or a thinnerpart on the portion facing the rupturable plate of the cup.
 4. Aninflator according to claim 1 or 3, wherein the fragile portion meetingthe requirement (b) is formed by providing one line notch or providingtwo or more line notches crossing perpendicularly to each other orcrossing obliquely thereto on a portion facing the rupturable plate, orby making the portion thinner in a circular shape or a shape similarthereto.
 5. An inflator according to claim 1, wherein, in the rupturableplate meeting the requirement (c), an explosive is attached to the sidefacing the igniter.
 6. An inflator according to claim 1, wherein thefragile portion meeting the requirement (d) is formed by partiallynotching or by making a thinner portion.
 7. An inflator according toclaim 1 or 6, wherein the fragile portion meeting the requirement (d) isformed by providing one line notch or providing two or more line notchescrossing perpendicularly to each other or crossing obliquely thereto ona portion facing the rupturable plate, or by making the portion thinnerin a circular shape or a shape similar thereto.
 8. An inflator accordingto claim 1, which is provided with the requirement (a) and therequirement (b).
 9. An inflator according to any one of claims 1 to 8,wherein the igniter and the rupturable plate are arranged to face eachother at a predetermined interval.
 10. An inflator according to any oneof claims 1 to 9, wherein the rupturable plate is in a bowl-like shapeprojecting to the igniter side.
 11. An inflator according to any one ofclaims 1 to 10, wherein the rupturable plate is mounted to the openingportion of the inflator housing or the diffuser portion.
 12. An inflatorcomprising an inflator housing in which a pressurized medium is chargedand one end is provided with an opening, a diffuser portion which isconnected to the opening portion of the inflator housing and is providedwith a gas discharging hole for discharging the pressurized mediumflowing from the opening portion to the outside at actuation, therupturable plate closing outflow path for the pressurized medium betweenthe opening of the inflator housing and the diffuser portion, and anigniter which includes a priming for rupturing the rupturable plate byan detonation wave and is provided in the diffuser portion, wherein oneor combination of at least two requirements selected from the followingrequirements (a) to (c) are provided: (a) the rupturable plate has anotch. (b) a filter is arranged at the gas discharging hole. (c) achemical agent containing perchlorate as a main component in an amountof 280 mg or less is used as a priming for rupturing the rupturableplate.
 13. An inflator wherein the rupturable plate meeting therequirement (a) has at least two notches crossing perpendicularly orobliquely.
 14. An inflator according to claim 12 or 13, wherein therupturable plate meeting the requirement (a) has a cross-shaped notch, aX-like shaped notch or a Y-like shaped notch.
 15. An inflator accordingto claim 12, further comprising a gas discharging port connected at thegas discharging hole, wherein the pressurized medium flowing out fromthe gas discharging hole passes the gas discharging port to bedischarged from an opening portion of the gas discharging port, and thefilter meeting the requirement (b) is arranged in the gas dischargingport.
 16. An inflator according to claim 15, wherein the filter meetingthe requirement (b) is disposed in the opening portion of the gasdischarging port.
 17. An inflator according to claim 12, wherein theperchlorate meeting the requirement (C) is zirconium/potassiumperchlorate and the rupturable plate is a nickel base alloy with athickness of 0.8 mm or less.
 18. An inflator according to any one ofclaims 12 to 17, wherein the rupturable plate is mounted to the openingportion of the inflator housing or the diffuser portion.
 19. An inflatorcomprising an inflator housing in which a pressurized medium is chargedand one end is provided with an opening portion, a diffuser portionwhich is connected to the opening portion of the inflator housing and isprovided with a gas discharging hole for discharging the pressurizedmedium flowing from the opening portion of the inflator housing to theoutside at a time of actuation, a rupturable plate closing an outflowpath for the pressurized medium between the diffuser portion and theopening portion of the inflator housing, and a rupturing means for therupturable plate is provided in the diffuser portion, wherein therupturable plate is mounted at an annular member fitted to be integratedwith the opening portion of the inflator housing.
 20. An inflatoraccording to claim 19, wherein the pressurized medium is charged from aclearance between the end edge of the opening portion in the inflatorhousing and the annular member, and the opening portion of the inflatorhousing and the annular member are joined to each other by aresistance-welding.
 21. An inflator comprising an inflator housing inwhich a pressurized medium is charged and one end is provided with anopening portion, a diffuser portion which is connected to the openingportion of the inflator housing and is provided with a gas discharginghole for discharging the pressurized medium flowing from the openingportion to the outside at actuation, a rupturable plate closing anoutflow path for the pressurized medium between the diffuser portion andthe opening portion of the inflator housing, and a rupturing means forthe rupturable plate provided in the diffuser portion, wherein theinflator housing is connected to the diffuser portion by screwing. 22.An inflator according to claim 21, wherein the connection of theinflator housing and the diffuser portion is achieved by screwing ascrew portion on an outer surface of an end portion in the inflatorhousing to a screw portion on an inner surface of an end portion in thediffuser portion.
 23. An inflator comprising an inflator housing inwhich a pressurized medium is charged and one end is provided with anopening, a diffuser portion which is fixed to the opening portion of theinflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at actuation, a rupturable plate closing an outflow path forthe pressurized medium between the diffuser portion and the openingportion of the inflator housing, and a rupturing means for therupturable plate provided in the diffuser portion, wherein the outflowdirection of the pressurized medium at actuation is coincident with theaxial direction of the inflator housing.
 24. An inflator comprising aninflator housing in which a pressurized medium is charged and one end isprovided with an opening, a diffuser portion which is fixed to theopening portion of the inflator housing and is provided with a gasdischarging hole for discharging the pressurized medium flowing from theopening portion to the outside at actuation, a rupturable plate closingan outflow path for the pressurized medium between the diffuser portionand the opening portion of the inflator housing, and a rupturing meansfor the rupturable plate provided in the diffuser portion, wherein a gasdischarging port connected to the gas discharging hole is furtherprovided, and the pressurized medium discharged from the gas discharginghole passes the gas discharging port to be discharged from the openingportion of the gas discharging port.
 25. An inflator according to claim24, wherein the gas discharging port is mounted such that the axialdirection of the gas discharging port and the axial direction of theinflator housing are parallel with each other.
 26. An inflatorcomprising an inflator housing in which a pressurized medium is chargedand one end is provided with an opening, a diffuser portion which isfixed to the opening portion of the inflator housing and is providedwith a gas discharging hole for discharging the pressurized mediumflowing from the opening portion to the outside at actuation, arupturable plate closing an outflow path for the pressurized mediumbetween the diffuser portion and the opening portion of the inflatorhousing, and a rupturing means for the rupturable plate provided in thediffuser portion, wherein the gas discharging port is disposed in theextension of the center line of the opening portion in the inflatorhousing, and the pressurized medium discharged from the gas discharginghole passes the gas discharging port to be discharged from the openingportion of the gas discharging port.
 27. An inflator according to claim26, wherein the pressurized medium passes the opening portion of theinflator housing, the inner space of the diffuser portion and the gasdischarging port to be discharged from the opening portion of the gasdischarging port without changing the outflow direction of thepressurized medium.
 28. An inflator according to claim 26 or 27, whereinthe rupturing means for the rupturable plate provided in the diffuserportion is arranged to face th0e inner space of the diffuser portion andto position slantingly with respect to the central line of therupturable plate.
 29. An inflator according to claim 26, 27 or 28,wherein an angle (θ) formed between the central axis of the rupturingmeans for the rupturable plate provided in the diffuser portion and thecentral line of the rupturable plate is acute.
 30. An inflator accordingto claim 26 or 27, wherein the rupturing means for the rupturable plateprovided in the diffuser portion is arranged to face the inner space ofthe diffuser portion and to cross the central line of the rupturableplate perpendicularly.
 31. An inflator according to claim 26, 27 or 30,wherein the rupturable plate closes the outflow path of the pressurizedmedium in the inner space of the diffuser portion and part of therupturable plate faces the rupturing means.
 32. An inflator according toclaim 31, wherein the rupturable plate is a cylindrical member havingone end closed and the other end open, it closes the outflow path of thepressurized medium with closed end and the peripheral surface thereof,and part of the peripheral surface faces the rupturing means.
 33. Aninflator according to anyone of claims 24 to 32, wherein the gasdischarging port comprises a cylindrical member having one end closedand the other end provided with an opening portion, and the pressurizedmedium flows out from the opening portion.
 34. An inflator according toany one of claims 23 to 33, wherein a filter for removing foreignobjects in the discharged pressurized medium is provided inside oroutside the gas discharging hole, or the gas discharging hole is formedwith the filter.
 35. An inflator according to any one of claims 24 to34, wherein a filter for removing foreign objects in the dischargedpressurized medium is provided inside the gas discharging port.
 36. Aninflator according to any one of claims 24 to 35, wherein a filter forremoving foreign objects in the discharged pressurized medium isprovided at the opening portion of the gas discharging port.
 37. Aninflator according to any one of claims 24 to 36, wherein an adapter fordischarging the pressurized medium in the circumferential direction ismounted to the opening portion of the gas discharging port to beattached and removed optionally.
 38. An inflator comprising an inflatorhousing in which a pressurized medium is charged and one end is providedwith an opening portion, a diffuser portion which is fixed to theopening portion of the inflator housing and is provided with a gasdischarging hole for discharging the pressurized medium flowing from theopening to the outside at actuation, a rupturable plate closing anoutflow path for the pressurized medium between the diffuser portion andthe opening portion of the inflator housing, and a rupturing means forthe rupturable plate provided in the diffuser portion, wherein anoutflow amount of the pressurized medium at actuation is controlled by agas discharging hole or a filter provided at the gas discharging hole.39. An inflator according to claim 38, wherein the filter is a annularshape, it covers the gas discharging hole of the diffuser portion fromthe inside and it is arranged to capture foreign objects contained inthe pressurized medium, and further an annular space having a sectionalarea in the radial direction larger than an opening area of the gasdischarging hole is formed between the annular filter and the gasdischarging hole to control the outflow amount of the pressurized mediumat actuation of the inflator by the gas discharging hole.
 40. Aninflator according to claim 39, wherein the sectional area of theannular filter in the radial direction is larger than the sectional areaof the annular space in the radial direction.
 41. An inflator accordingto any one of claims 38 to 40, wherein the annular filter is made of onelayered porous member such as a punched metal, a plain-stitched wiremesh or the similar member or at least two layered of the porousmembers.
 42. An inflator comprising an inflator housing in which apressurized medium is charged and one end is provided with an openingportion, a diffuser portion which is fixed to the opening portion of theinflator housing and is provided with a gas discharging hole fordischarging the pressurized medium flowing from the opening portion tothe outside at actuation, a rupturable plate closing an outflow path forthe pressurized medium between the diffuser portion and the opening ofthe inflator housing, and a rupturing means for the rupturable plateprovided in the diffuser portion, wherein a gas discharging portconnected at the gas discharging hole is provided, the pressurizedmedium discharged from the gas discharging hole passes the gasdischarging port to be discharged from the opening of the gasdischarging port, and the outflow amount of the pressurized medium atactuation is controlled by opening portion of the gas discharging portor a filter provided in the gas discharging port.
 43. An inflatorcomprising an inflator housing in which a pressurized medium is chargedand one end is provided with an opening portion, a diffuser portionwhich is fixed to the opening portion of the inflator housing and isprovided with a gas discharging hole for discharging the pressurizedmedium flowing from the opening to the outside at actuation, arupturable plate closing an outflow path for the pressurized mediumbetween the diffuser portion and the opening of the inflator housing,and a rupturing means for the rupturable plate provided in the diffuserportion, wherein the outflow amount of the pressurized medium atactuation is controlled by the outflow path of the pressurized medium.44. An inflator according to claim 42 or 43, further comprising a gasdischarging port having the opening portion connected at the gasdischarging hole of the diffuser portion wherein the pressurized mediumdischarged from the gas discharging hole passes is the gas dischargingport to be discharged from the opening portion of the gas dischargingport.
 45. An inflator according to any one of claims 42 to 44, whereinthe gas discharging port has two or more opening portions only on theside surface, at least two opening portions of the two or more openingportions are positioned symmetrically in the widthwise direction orpositioned similarly thereto, and a screen with a plurality of outflowholes is arranged at the position where the opening portion is providedinside the gas discharging port.
 46. An inflator according to claim 45,wherein the screen comprises a cylinder made of one layered porousmember such as a punched metal, a plain-stitched wire mesh or thesimilar member or at least two layered of the porous members.
 47. Aninflator according to claim 45 or 46, wherein the screen is arrangedsuch that its axial direction is coincident with the axial direction ofthe gas discharging port.
 48. An inflator according to any one of claims42, and 44 to 47, wherein, when the inflator is connected to the airbag, the gas discharging port has convex portions continuously in acircumferential direction or at intervals provided on an outer surfacefrom the at least two openings on the side surface to a portion where anair bag is connected.
 49. An inflator wherein, in connecting an air bagto an inflator according to claim 48, when the gas discharging port isinserted into a cylindrical mouthpiece mounted to the opening portion ofthe air bag and the mouthpiece and the gas discharging port areconnected to each other, a clearance exists between an inner surface ofthe mouthpiece and an outer surface of an inserted portion of the gasdischarging port reaching the convex portion, and a sectional area ofthe clearance defined by a difference between a widthwise sectional areain the mouthpiece and a widthwise sectional area in the inserted portionof the gas discharging port reaching the projecting portion thereof islarger than the total opening area of a outflow hole of a screenarranged at the gas discharging port.
 50. An inflator wherein, inconnecting an air bag to an inflator according to claim 49, when the gasdischarging port is inserted into a cylindrical mouthpiece mounted tothe opening portion of the air bag and the mouthpiece and the gasdischarging port are connected to each other, a clearance exists betweenan inner surface of the mouthpiece and an outer surface of an insertedportion of the gas discharging port reaching the convex portion, and asectional area of the clearance defined by a difference between awidthwise sectional area in the mouthpiece and a widthwise sectionalarea in the inserted portion of the gas discharging port reaching theprojecting portion thereof is larger than the total opening area of thegas discharging hole arranged at the diffuser portion.
 51. An inflatoraccording to claim 49 or 50, wherein a male screw is provided on theconvex portion of the gas discharging port, and a female screw isprovided on part of or the entire portion of the mouthpiece, and themouthpiece and the convex portion of the gas discharging port isconnected by screwing.
 52. An inflator according to any one of claims 49to 51, wherein a the width of clearance existing between the an innersurface of the mouthpiece and an outer surface of the inserted portionof the gas discharging port reaching the convex portion is in the rangeof 1 to 5 mm.
 53. An inflator according to any one of claims 23 to 52,wherein the rupturable plate is mounted to the opening portion of theinflator housing or the diffuser portion.
 54. A filter means for aninflator for removing foreign objects, comprising a disk-shapedsupporting body having a predetermined number of through holes, and afilter member covering one surface or both surfaces of the disk-shapedsupporting body.
 55. A filter means for an inflator according to claim54, wherein the filter member comprises a punched metal or metal lath.56. A filter means for an inflator according to claim 54 or 55, wherein,in case of the filter means in the filter member having a square mesh ofsieve, one side is in the range of 0.4 to 2.0 mm.
 57. A filter memberfor an inflator according to any one of claims 54 to 56, wherein, whenboth surfaces of the disk-shaped supporting body are covered with filtermembers, the meshes of sieve on the both faces of the filter members canbe equal to each other or different from each other.
 58. A filter meansfor an inflator according to any one of claims 54 to 57, wherein a screwportion for mounting inside the inflator to be attached and removedoptionally is provided on an outer peripheral surface of the disk-shapedsupporting body of the filter means.
 59. An inflator comprising aninflator housing in which a pressurized medium is charged and one end isprovided with an opening portion, a diffuser portion which is connectedto the opening portion of the inflator housing and is provided with agas discharging hole for discharging the pressurized medium flowing fromthe opening to the outside at actuation, a rupturable plate closing anoutflow path for the pressurized medium between the diffuser portion andthe opening portion of the inflator housing, and a rupturing means forthe rupturable plate provided in the diffuser portion, and wherein a gasdischarging port which is connected to the gas discharging hole and hasone end closed and other end with an opening portion, and one or atleast two filter means for an inflator according to any one of claims 54to 57 for removing foreign objects in the discharged pressurized mediumis provided inside the gas discharging port to be attached and removedoptionally and movable in the axial direction, and wherein thepressurized medium discharged from the gas discharging hole passes thegas discharging port to be discharged from the opening portion of thegas discharging port.
 60. An inflator according to claim 59, wherein twoor more filter means are arranged to be in contact with each other orthey are spaced from each other.
 61. An inflator according to claim 59or 60, wherein, two or more filter means have the same meshes of sieveor different meshes of sieve of the respective filter members.
 62. Aninflator according to any one of claims 59 to 61, wherein two or morefilter means has different meshes of sieve of the respective filtermembers, and the two or more filter means are arranged such that themeshes of sieve become gradually smaller from the gas discharging holeof the diffuser portion towards the opening portion of the gasdischarging port.
 63. An inflator according to any one of claims 59 to62, wherein a screw portion is provided on an inner circumferentialsurface of the gas discharging port and the disk-shaped supporting bodyof the filter means for an inflator is screwed to be mounted to beattached and removed optionally
 64. An inflator according to any one ofclaims 59 to 63, wherein the gas discharging port is mounted such thatthe axial direction of the gas discharging port and the axial directionof the inflator housing are parallel to each other.
 65. An inflatoraccording to any one of claims 59 to 64, where an adapter fordischarging the pressurized medium in the circumferential direction ismounted to the opening portion of the gas discharging port to beattached and removed optionally.
 66. An air bag apparatus provided withan activation signal-outputting means comprising an impact sensor and acontrol unit, and a module case accommodating an inflator according toany one of claims 1 to 55 and 59 to 65 and an air bag.